UNIVERSITY  OF  CALIFORNIA 
LOS  ANGELES 


ANALYSIS   OF 

PAINT  VEHICLES,  JAPANS 

AND  VARNISHES 


ANALYSIS  OF 

PAINT  VEHICLES,  JAPANS 

AND  VAENISHES 


BY 
CLIFFORD  DYER  HOLLEY,   M.S.,   PH.D. 

PROFESSOR  CHEMICAL  ENGINEERING,  UNIVERSITY  OF  MICHIGAN 
AND  CHIEF  CHEMIST  ACME  WHITE  LEAD  A,   COLOR  WORKS 


NEW  YORK 

JOHN    WILEY    &    SONS,    INC. 

LONDON:  CHAPMAN  &  HALL,  LIMITED 

1920 


PHILADELPHIA  BOOK  COMPANY 
22  North  Ninth  Street,  Philadelphia,  Pa. 


COPYRIGHT -1920 
BY    CLIFFORD    DYER    HOLLEY 


THE-PLIMPTON-PBESS-NORWOOD-MASS-U-S-A 


TP 


JL  HE  author  wishes  to  express  his  appreciation 
for  the  suggestions  and  assistance  rendered  by 
M.  H.  Ryan,  The  Acme  White  Lead  &  Color 
Works;  H.  A.  Gardner,  Institute  of  Industrial 
Research;  H.  H.  Willard,  University  of  Michigan; 
L.  V.  Pulsifer,  Valentine  &  Company;  and  G.  W. 
Thompson,  National  Lead  Company. 


EHGIH 


SARY 


PREFACE 

THE  great  progress  in  the  development  of  the 
Paint,  Enamel  and  Varnish  Industries  which  has 
marked  the  past  decade  has  brought  with  it  an 
urgent  necessity  for  systematic  methods  of  analysis, 
particularly  with  reference  to  the  vehicles  used.  Due 
to  the  increased  number  of  technical  men  working  in 
these  industries,  great  advances  have  been  made  in 
the  discovery,  processing  and  utilization  of  a  number 
of  oils,  and  other  vehicles  which  have  not  heretofore 
found  extended  use  in  the  paint  and  varnish  trade. 

The  methods  of  analysis  here  presented  are  essen- 
tially those  used  by  the  author  in  his  laboratory 
work.  Many  of  them  are  the  results  of  extended 
investigation  conducted  by  him  and  his  associates, 
others  represent  the  best  thought  of  representative 
technologists,  and  have  been  adopted  as  standard 
methods  by  the  American  Society  For  Testing 
Materials. 

In  the  arrangement  and  presentation  of  the  sub- 
ject matter,  the  needs  of  the  analyst  have  been  kept 
constantly  in  view,  and  it  is  the  hope  of  the  author 
that  this  book  will  prove  of  material  value  to  all  those 
engaged  in  the  manufacture  and  examination  of  paint, 
enamel  and  varnish  products. 

CLIFFORD  D.  HOLLEY 

DETROIT,  MICHIGAN 

October  10,  1919 


CONTENTS 

CHAPTER  PAGE 

I.  EXAMINATION  OF  PETROLEUM  THINNERS      ....  1 

II.  EXAMINATION  OF  PETROLEUM  THINNERS  (continued)        .  14 

III.  EXAMINATION  OF  TURPENTINE 28 

IV.  ALCOHOLS  AND  ACETONES       .        .      ...      .      .  35 

V.  BENZOL  AND  SOLVENT  NAPHTHAS    ......  49 

VI.  LINSEED  OIL 52 

VII.  LINSEED  OIL  (continued)           65 

VIII.  TUNG  OIL  (CHINESE  WOOD  OIL) 79 

LX.  MISCELLANEOUS  PAINT  AND  VARNISH  OILS  ....  91 

X.  SEPARATION  OF  VEHICLE  FROM  PIGMENT      ....  96 

XI.  ESTIMATION  OF  WATER  IN  PAINTS 105 

XII.  WATER  EMULSIONS  AND  EMULSIFIERS 109 

XIII.  DETERMINATION  OF  VOLATILE  THINNER 115 

XIV.  EXAMINATION  OF  THE  EXTRACTED  OIL 122 

XV.  EFFECT  OF  STORAGE  ON  THE  COMPOSITION  OF  PAINTS     .  131 

XVI.  ANALYSIS  OF  SOLID  AND  LIQUID  DRIERS       ....  138 

XVII.   COMPARATIVE  ANALYSIS  OF  BLACK  BAKING  JAPANS  .       .  154 

XVIII.   ANALYSIS  OF  SHELLAC  AND  LACQUERS 167 

XLX.  ANALYSIS  OF  VARNISH  AND  ENAMEL  LIQUIDS      .       .       .  180 

XX.  ANALYSIS  OF  VARNISH  AND  ENAMEL  LIQUIDS  (continued)  189 

ADDENDA 196 

INDEX    .  197 


ANALYSIS  OF  PAINT  VEHICLES 
JAPANS  AND  VARNISHES 

CHAPTER  I 

EXAMINATION   OF  PETROLEUM   THINNERS 

1.  The    enormous    increase,  during    the    past    ten 
years,  in  the  use  of  petroleum  thinners  in  the  manu- 
facture of  paints  and  varnishes,  both  for  general  and 
special  uses,  and  the  successful  results  obtained  with 
them    necessitate    on    the    part    of    the    chemist    a 
thorough   and    consistent    procedure   of   examination 
of    this    class    of    products.     The    methods    adopted 
should  be  rapid  and  at  the  same  time  yield  results 
that  can  be  closely  duplicated,  not  only  by  the  same 
operator,  but  by  others. 

2.  Odor.    All   petroleum   naphthas    or   turpentine 
substitutes    should    have    a    pleasant    and    agreeable 
odor.     A  penetrating  disagreeable  odor,  suggestive  of 
sulphur  compounds,  or  a  strong  gaseous  odor  becomes 
highly  intensified  when   such  products  are  used  as 
components  of  paints  or  enamels  and  allowed  to  re- 
main in  sealed  packages  for  some  time.    A  sample 
or  shipment  having  a  questionable  odor  should  be 
placed  in  a  closed  can  or  flask,  allowing  considerable 
air  space,  and  kept  for  at  least  three  days  hi  a  warm 
place.    If  the  odor  has  become  materially  stronger 


2  PAINT   VEHICLES.   JAPANS   AND   VARNISHES 

and  more  disagreeable  in   character,   the  sample  or 
shipment  should  be  regarded  unfavorably. 

3.  Color.    The  color  should  be  water  white,  have 
no  yellow  cast  or  evidence  of  a  bloom.     This  is  best 
observed  by  placing  side  by  side  in  500-c.c.  beakers, 
on  a  white  surface,   samples  of  the  material  to  be 
tested  and  the  standard. 

4.  Solvent   strength.     It   is   well   known   that   pe- 
troleum thinners  having  substantially  the  same  dis- 
tillation figures  may  vary  greatly  in  their  ability  to 
hold  in  solution  the  varnish  gums.     In  the  manu- 
facture and  use  of  varnishes  made  without  turpentine 
it  is  necessary  to  select  petroleum  thinners  of  the 
greatest  solvent  strength  consistent  with  the  work- 
ing, drying  and  other  necessary  features. 

A  definite  and  practical  test  for  the  solvent  strength 
of  any  petroleum  thinner  may  be  made  by  selecting 
a  short  oil  kauri  varnish  containing  no  turpentine; 
for  example,  one  made  from  100  Ibs.  kauri,  7  gals,  of 
linseed  oil  and  25-30  gals,  of  an  accepted  turpentine 
substitute.  The  method  of  procedure  used  by  the 
author  is  as  follows:  Pour  into  a  6-oz.  graduate  2  oz. 
of  the  varnish.  Add  carefully,  by  allowing  to  flow 
down  the  side  of  the  graduate  so  as  not  to  mix  with 
the  varnish,  2  oz.  of  the  thinner  to  be  tested.  The 
two  layers  are  now  mixed  by  vigorous  stirring;  a  slight 
break  may  be  noticed,  but  the  thinner  should 
dissolve  the  broken-out  portion  without  difficulty. 
If  the  thinner  stands  this  test,  further  additions  of 
the  thinner  in  |-oz.  portions  should  be  made  in  the 
same  manner  till  a  permanent  break  is  obtained.  If 
properly  conducted  the  above  test  will  give  very  ac- 
curate information  as  to  the  solvent  strength  of  any 
thinner.  It  is,  however,  necessary  to  take  a  few 


EXAMINATION   OF   PETROLEUM  THINNERS  3 

simple  precautions,  such  as  keeping  the  temperature 
constant,  and  adopting  a  strictly  uniform  procedure 
for  the  addition  of  the  thinner  to  be  tested. 

In  conducting  the  above  test  a  freshly  drawn  sample 
of  varnish  should  be  used,  or  else  the  varnish  should 
be  kept  in  a  completely  filled  can,  as  continued  ex- 
posure to  the  air,  such  as  occurs  in  a  partially  filled 
package,  materially  affects  the  solubility  of  the  gum. 

Many  of  the  complaints  received  from  the  users 
of  varnish  and  enamel  products  are  caused  by  the 
gradual  breaking  out  of  the  gums  from  solution. 
Often  two  to  six  months  will  elapse  before  the  de- 
terioration is  observable;  primarily  it  is  due  to  the 
use  of  thinners  of  low  solvent  strength  and,  there- 
fore, in  the  testing  a  generous  margin  of  safety  should 
be  observed. 

5.  Specific  gravity.  The  manufacturers  of  petro- 
leum products  use  the  Beaume  scale  exclusively. 
The  chemist,  therefore,  should  be  provided  with  an 
accurate  set  of  Tagliabue  hydrometers,  including  the 
following : 

19°  to  31°  Be.  equivalent  to  0. 9402  to  0. 8708  Sp.  Gr. 
29°  "  41°    "  "          "  0.8816  "  0.8203    "     " 

39°  "  51°    "  "          "  0.8299  "  0.7753    "     " 

49°  "  61°    "  "          "  0.7839  "  0.7351    "     " 

The  gravity  is  determined  without  cooling  and  the 
temperature  correction  made  according  to  the  follow- 
ing tables.  At  60°  F.  the  indications  of  the  hydrom- 
eter require  no  correction;  below  that  temperature 
the  indications  are  too  low,  above  it,  too  high.  Sup- 
pose the  hydrometer  reads  54°  Be.  and  thermometer 
40°  F.,  the  corrected  reading  of  56.1°  Be.  for  60°  F.  is 
found  in  the  temperature  column  under  40°  and  oppo- 
site the  indication  54.  If  the  reading  is  desired  in 
terms  of  specific  gravity,  Table  II  may  be  used. 


4  PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

This  table  is  the  one  according  to  which  the  Tag- 
liabue  hydrometers  are  made,  being  based  on  the 
formula 


S.G.     : 


131.5+  B 

and  is  the  one  universally  used  by  the  petroleum 
manufacturers  and  refiners.  Lately  the  modulus  140, 
as  expressed  by  the  formula 

140 

0T 

has  been  urged.  The  oil  trade,  however,  has  shown 
little,  if  any,  disposition  to  adopt  it." 


EXAMINATION   OF  PETROLEUM   TH1NNERS 

TABLE  I 
6.  Temperature  Corrections 


Indication  i 

TEMPERATURES 

40° 

41° 

42° 

43° 

44° 

45° 

46° 

47° 

48° 

49° 

If) 

16.0 

16.0 

15.9 

15.9 

15.8 

15.8 

15.7 

15.7 

15.6 

15.6 

It) 

17.1 

17.1 

17.0 

16.9 

16.9 

16.8 

16.8 

16.7 

16.6 

16.6 

17 

18.1 

18.1 

18.0 

17.9 

17.9 

17.8 

17.8 

17.7 

17.6 

17.6 

L8 

19.1 

19. 

19.0 

18.9 

18.9 

18.8 

18.8 

18.7 

18.6 

18.6 

19 

20.1 

20. 

20.0 

19.9 

19.9 

19.8 

19.8 

19.7 

19.6 

19.6 

20 

21.1 

21. 

21.0 

20.9 

20.9 

20.8 

20.7 

20.7 

20.6 

20.6 

n 

22.1 

22. 

22.0 

21.9 

21.9 

21.8 

21.8 

21.7 

21.6 

21.6 

12 

23.2 

23. 

23.0 

23.0 

22.9 

22.8 

22.8 

22.7 

22.7 

22.6 

s 

24.2 

24. 

24.1 

24.0 

23.9 

23.9 

23.8 

23.7 

23.7 

23.6 

>A 

25.2 

25.2 

25.1 

25.0 

25.0 

24.9 

24.8 

24.8 

24.7 

24.6 

}5 

26.3 

26.2 

26.1 

26.1 

26.0 

25.9 

25.8 

25.8 

25.7 

25.6 

26 

27.3 

27.2 

27.2 

27.1 

27.0 

26.9 

26.9 

26.8 

26.7 

26.7 

27 

28.3 

28.2 

28.2 

28.1 

28.0 

28.0 

27.9 

27.8 

27.8 

27.7 

28 

29.3 

29.3 

29.2 

29.1 

29.1 

29.0 

28.9 

28.8 

28.8 

28.7 

29 

30.4 

30.3 

30.2 

30.1 

30.1 

30.0 

29.9 

29.9 

29.8 

29.7 

50 

31.4 

31.3 

31.2 

31.2 

31.1 

31.0 

31.0 

30.9 

30.8 

30.7 

51 

32.4 

32.4 

32.3 

32.2 

32.1 

32.1 

32.0 

31.9 

31.8 

31.8 

52 

33.5 

33.4 

33.3 

33.2 

33.1 

33.1 

33.0 

32.9 

32.9 

32.8 

53 

34.5 

34.4 

34.3 

34.2 

34.2 

34.1 

34.0 

34.0 

33.9 

33.8 

54 

35.5 

35.4 

35.4 

35.3 

35.2 

35.1 

35.1 

35.0 

34.9 

34.8 

(5 

36.5 

36.5 

36.4 

36.3 

36.2 

36.2 

36.1 

36.0 

35.9 

35.8 

56 

37.6 

37.5 

37.4 

37.3 

37.2 

37.2 

37.1 

37.0 

36.9 

36.8 

57 

38.6 

38.5 

38.4 

38.3 

38.3 

38.2 

38.1 

38.0 

37.9 

37.9 

(8 

39.6 

39.5 

39.4 

39.4 

39.3 

39.2 

39.1 

39.0 

39.0 

38.9 

59 

40.6 

40.5 

40.5 

40.4 

40.3 

40.2 

40.1 

40.1 

40.0 

39.9 

10 

41.6 

41.6 

41.5 

41.4 

41.3 

41.2 

41.2 

41.1 

41.0 

40.9 

u 

42.7 

42.6 

42.5 

42.4 

42.3 

42.3 

42.2 

42.1 

42.0 

41.9 

t2 

43.7 

43.6 

43.5 

43.4 

43.4 

43.3 

43.2 

43.1 

43.0 

42.9 

13 

44.7 

44.6 

44.5 

44.5 

44.4 

44.3 

44.2 

44.1 

44.0 

44.0 

14 

45.7 

45.7 

45.6 

45.5 

45.4 

45.3 

45.2 

45.2 

45.1 

45.0 

15 

46.8 

46.7 

46.6 

46.5 

46.4 

46.3 

46.3 

46.2 

46.1 

46.0 

to 

47.8 

47.7 

47.6 

47.5 

47.4 

47.3 

47.3 

47.2 

47.1 

47.0 

17 

48.8 

48.7 

48.6 

48.6 

48.5 

48.4 

48.3 

48.2 

48.1 

48.0 

18 

49.9 

49.8 

49.7 

49.6 

49.5 

49.4 

49.3 

49.2 

49.1 

49.0 

19 

,50.9 

50.8 

50.7 

50.6 

50.5 

50.4 

50.3 

50.2 

50.1 

50.0 

>0 

52.0 

51.9 

51.8 

51.7 

51.6 

51.5 

51.4 

51.3 

51.2 

51.1 

>1 

53.0 

52.9 

52.8 

52.7 

52.6 

52.5 

52.4 

52.3 

52.2 

52.1 

)2 

54.0 

53.9 

53.8 

53.7 

53.6 

53.5 

53.4 

53.3 

53.2 

53.1 

3 

55.1 

55.0 

54.9 

54.8 

54.6 

54.5 

54.4 

54.3 

54.2 

54.1 

>4 

56.1 

56.0 

55.9 

55.8 

55.7 

55.6 

55.5 

55.4 

55.2 

55.1 

>5 

57.1 

57.0 

56.9 

56.8 

56.7 

56.6 

56.5 

56.4 

56.3 

56.2 

>G 

58.2 

58.1 

58.0 

57.9 

57.8 

57.7 

57.5 

57.4 

57.3 

57.2 

>7 

59.2 

59.1 

59.0 

58.9 

58.8 

58.7 

58.5 

58.4 

58.3 

58.2 

>8 

60.3 

60.1 

60.0 

59.9 

59.8 

59.7 

59.6 

59.4 

59.3 

59.2 

>9 

61.3 

61.2 

61.1 

61.0 

60.8 

60.7 

60.6 

60.5 

60.4 

60.2 

)0 

62.3 

62.2 

61.2 

62.0 

61.9 

61.7 

61.6 

61.5 

61.4 

61.3 

PAINT  VEHICLES,   JAPANS  AND   VARNISHES 


j 

TEMPERATURES 

50° 

51° 

52° 

53° 

64° 

65° 

56° 

67° 

58° 

69° 

15 

15.5 

15.5 

15.4 

15.4 

15.3 

15.3 

15.2 

15.2 

15.1 

15.1 

16 

16.5 

16.5 

16.4 

16.4 

16.3 

16.3 

16.2 

16.2 

16.1 

16.1 

17 

17.5 

17.5 

17.4 

17.4 

17.3 

17.3 

17.2 

17.2 

17.1 

17.1 

18 

18.5 

18.5 

18.4 

18.4 

18.3 

18.3 

18.2 

18.2 

18.1 

18.1 

19 

19.5 

19.5 

19.4 

19.4 

19.3 

19.3 

19.2 

19.2 

19.1 

19.1 

20 

20.5 

20.5 

20.4 

20.4 

20.3 

20.3 

20.2 

20.2 

20.1 

20. 

21 

21.5 

21.5 

21.4 

21.4 

21.3 

21.3 

21.2 

21.2 

21.1 

21. 

22 

22.5 

22.5 

22.4 

22.4 

22.3 

22.3 

22.2 

22.2 

22.1 

22. 

23 

23.6 

23.5 

23.5 

23.4 

23.4 

23.3 

23.2 

23.2 

23.1 

23. 

24 

24.6 

24.5 

24.5 

24.4 

24.4 

24.3 

24.3 

24.2 

24.1 

24. 

25 

25.6 

25.5 

25.5 

25.4 

25.4 

25.3 

25.3 

25.2 

25.1 

25. 

26 

26.6 

26.5 

26.5 

26.4 

26.4 

26.3 

26.3 

26.2 

26.1 

26. 

27 

27.6 

27.6 

27.5 

27.4 

27.4 

27.3 

27.3 

27.2 

27.1 

27. 

28 

28.6 

28.6 

28.5 

28.4 

28.4 

28.3 

28.3 

28.2 

28.1 

28. 

29 

29.7 

29.6 

29.5 

29.5 

29.4 

29.3 

29.3 

29.2 

29.1 

29. 

30 

30.7 

30.6 

30.5 

30.5 

30.4 

30.3 

30.3 

30.2 

30.1 

30. 

31 

31.7 

31.6 

31.6 

31.5 

31.4 

31.3 

31.3 

31.2 

31.1 

31. 

32 

32.7 

32.6 

32.6 

32.5 

32.4 

32.4 

32.3 

32.2 

32.1 

32. 

33 

33.7 

33.7 

33.6 

33.5 

33.4 

33.4 

33.3 

33.2 

33.2 

33. 

34 

34.8 

34.7 

34.6 

34.5 

34.5 

34.4 

34.3 

34.2 

34.2 

34. 

35 

35.8 

35.7 

35.6 

35.5 

35.5 

35.4 

35.3 

35.2 

35.2 

35. 

36 

36.8 

36.7 

36.6 

36.5 

36.5 

36.4 

36.3 

36.2 

36.2 

36. 

37 

37.8 

37.7 

37.6 

37.5 

37.5 

37.4 

37.3 

37.2 

37.2 

37. 

38 

38.8 

38.7 

38.6 

38.6 

38.5 

38.4 

38.3 

38.2 

38.2 

38. 

39 

39.8 

39.7 

39.7 

39.6 

39.5 

39.4 

39.3 

39.2 

39.2 

39. 

40 

40.8 

40.7 

40.7 

40.6 

40.5 

40.4 

40.3 

40.2 

40.2 

40. 

41 

41.8 

41.8 

41.7 

41.6 

41.5 

41.4 

41.3 

41.2 

41.2 

41. 

42 

42.9 

42.8 

42.7 

42.6 

42.5 

42.4 

42.3 

42.3 

42.: 

42. 

43 

43.9 

43.8 

43.7 

43.6 

43.5 

43.4 

43.3 

43.3 

43.1 

43. 

44 

44.9 

44.8 

44.7 

44.6 

44.5 

44.4 

44.4 

44.3 

44.' 

44. 

45 

45.9 

45.8 

45.7 

45.6 

45.5 

45.5 

45.4 

45.3 

45.2 

45. 

46 

46.9 

46.8 

46.7 

46.6 

46.6 

46.5 

46.4 

46.3 

46.2 

46. 

47 

47.9 

47.8 

47.7 

47.7 

47.6 

47.5 

47.4 

47.3 

47.2 

47. 

48 

48.9 

48.9 

48.8 

48.7 

48.6 

48.5 

48.4 

48.3 

48.2 

48. 

49 

50.0 

49.9 

49.8 

49.7 

49.6 

49.5 

49.4 

49.3 

49  2 

49. 

50 

51.0 

50.9 

50.8 

50.7 

50.6 

50.5 

50.4 

50.3 

50  2 

50. 

51 

52.0 

51.9 

51.8 

51.7 

51.6 

51.5 

51.4 

51.3 

51  2 

51. 

52 

53.0 

52.9 

52.8 

52.7 

52.6 

52.5 

52.4 

52.3 

52.2 

52. 

53 

54.0 

53.9 

53.8 

53.7 

53.6 

53.5 

53.4 

53.3 

53.2 

53. 

54 

55.0 

54.9 

54.8 

54.7 

54.6 

54.5 

54.4 

54.3 

54.2 

54. 

55 

56.1 

56.0 

55.9 

55.8 

55.7 

55.5 

55.4 

55.3 

55.2 

55. 

56 

57.1 

57.0 

56.9 

56.8 

56.7 

56.5 

56.4 

56.3 

56.2 

56. 

57 

58.1 

58.0 

57.9 

57.8 

57.7 

57.5 

57.4 

57.3 

57.2 

57. 

58 

59.1 

59.0 

58.9 

58.8 

58.7 

58.5 

58.4 

58.3 

58.2 

58.1 

59 

60.1 

60.0 

59.9 

59.8 

59.7 

59.6 

59.5 

59.3 

59.2 

59.1 

60 

61.1 

61.0 

60.9 

60.8 

60.7 

60.6 

60.5 

60.3 

60.2 

60.1 

EXAMINATION   OF   PETROLEUM   THINNERS 


Indication 

TEMPERATUBES 

60° 

61° 

62° 

63° 

64° 

65° 

66° 

67° 

68° 

69° 

15 

15.0 

15.0 

14.9 

14.8 

14.8 

14.7 

14.7 

14.6 

14.5 

14.5 

16 

16.0 

16.0 

15.9 

15.8 

15.8 

15.7 

15.7 

15.6 

15.5 

15.5 

17 

17.0 

17.0 

16.9 

16.8 

16.8 

16.7 

16.7 

16.6 

16.5 

16.5 

18 

18.0 

18.0 

17.9 

17.8 

17.8 

17.7 

17.7 

17.6 

17.5 

17.5 

19 

19.0 

19.0 

18.9 

18.8 

18.8 

18.7 

18.7 

18.6 

18.5 

18.5 

20 

20.0 

19.9 

19.9 

19.8 

19.8 

19.7 

19.6 

19.6 

19.5 

19.5 

21 

21.0 

20.9 

20.9 

20.8 

20.7 

20.7 

20.6 

20.6 

20.5 

20.4 

22 

22.0 

21.9 

21.9 

21.8 

21.7 

21.7 

21.6 

21.5 

21.5 

21.4 

23 

23.0 

22.9 

22.9 

22.8 

22.7 

22.7 

22.6 

22.5 

22.5 

22.4 

24 

24.0 

23.9 

23.9 

23.8 

23.7 

23.7 

23.6 

23.5 

23.5 

23.4 

25 

25.0 

24.9 

24.9 

24.8 

24.7 

24.7 

24.6 

24.5 

24.5 

24.4 

26 

26.0 

25.9 

25.9 

25.8 

25.7 

25.7 

25.6 

25.5 

25.5 

25.4 

27 

27.0 

26.9 

26.9 

26.8 

26.7 

26.7 

26.6 

26.5 

26.5 

26.4 

28 

28.0 

25.9 

27.9 

27.8 

27.7 

27.7 

27.6 

27.5 

27.5 

27.4 

29 

29.0 

28.9 

28.9 

28.8 

28.7 

28.7 

28.6 

28.5 

28.5 

28.4 

30 

30.0 

29.9 

29.9 

29.8 

29.7 

29.7 

29.6 

29.5 

29.5 

29.4 

31 

31.0 

30.9 

30.9 

30.8 

30.7 

30.6 

30.6 

30.5 

30.4 

30.4 

32 

32.0 

31.9 

31.9 

31.8. 

31.7 

31.6 

31.6 

31.5 

31.4 

31.4 

33 

33.0 

32.9 

32.8 

32.8 

32.7 

32.6 

32.6 

32.5 

32.4 

32.4 

34 

34.0 

33.9 

33.8 

33.8 

33.7 

33.6 

33.5 

33.5 

34.4 

33.3 

35 

35.0 

34.9 

34.8 

34.8 

34.7 

34.6 

34.5 

34.5 

34.4 

34.3 

36 

36.0 

35.9 

35.8 

35.8 

35.7 

35.6 

35.5 

35.5 

35.4 

35.3 

37 

37.0 

36.9 

36.8 

36.8 

36.7 

36.6 

36.5 

36.5 

36.4 

36.3 

38 

38.0 

37.9 

37.8 

37.8 

37.7 

37.6 

37.5 

37.5 

37.4 

37.3 

39 

39.0 

38.9 

38.8 

38.8 

38.7 

38.6 

38.5 

38.4 

38.4 

38.3 

40 

40.0 

39.9 

39.8 

39.8 

39.7 

39.6 

39.5 

39.4 

39.4 

39.3 

41 

41.0 

40.9 

40.8 

40.8 

40.7 

40.6 

40.5 

40.4 

40.3 

40.3 

42 

42.0 

41.9 

41.8 

31.7 

41.7 

41.6 

41.5 

41.4 

41.3 

41.3 

43 

43.0 

42.9 

42.8 

42.7 

42.7 

42.6 

42.5 

42.4 

42.3 

42.2 

44 

44.0 

43.9 

43.8 

43.7 

43.6 

43.6 

43.5 

43.4 

43.3 

43.2 

45 

45.0 

44.9 

44.8 

44.7 

44.6 

44.6 

44.5 

44.4 

44.3 

44.2 

46 

46.0 

45.9 

45.8 

45.7 

45.6 

45.5 

45.5 

45.4 

45.3 

45.2 

47 

47.0 

46.9 

46.8 

46.7 

46.6 

46.5 

46.5 

46.4 

46.3 

46.2 

48 

48.0 

47.9 

47.8 

47.7 

47.6 

47.5 

47.4 

47.4 

47.3 

47.2 

49 

49.0 

48.9 

48.8 

48.7 

48.6 

48.5 

48.4 

48.3 

48.3 

48.2 

50 

50.0 

49.9 

49.8 

49.7 

49.6 

49.5 

49.4 

49.3 

49.2 

49.1 

51 

51.0 

50.9 

50.8 

50.7 

50.6 

50.5 

50.4 

50.3 

50.2 

50.1 

52 

52.0 

51.9 

51.8 

51.7 

51.6 

51.5 

51.4 

51.3 

51.2 

51.1 

53 

53.0 

52.9 

52.8 

52.7 

52.6 

52.5 

52.4 

52.3 

52.2 

52.1 

54 

54.0 

53.9 

53.8 

53.7 

53.6 

53.5 

53.4 

53.3 

53.2 

53.1 

55 

55.0 

54.9 

54.8 

54.7 

54.6 

54.5 

54.4 

54.3 

54.2 

54.1 

56 

56.0 

55.9 

55.8 

55.7 

55.6 

55.5 

55.4 

55.3 

55.2 

55.1 

57 

57.0 

56.9 

56.8 

56.7 

56.6 

56.5 

56.4 

56.2 

56.1 

56.0 

58 

58.0 

57.9 

57.8 

57.7 

57.6 

57.5 

57.3 

57.2 

57.1 

57.0 

59 

59.0 

58.9 

58.8 

58.7 

58.6 

58.5 

58.3 

58.2 

58.1 

58.0 

60 

60.0 

59.0 

59.8 

59.7 

59.6 

59.4 

59.3 

59.2 

59.1 

59.0 

PAINT  VEHICLES,   JAPANS  AND   VARNISHES 


5 

1 
i 

q 

TEMPERATURES 

70° 

71° 

72° 

73° 

74° 

75° 

76° 

77° 

78° 

79° 

15 

14.4 

14.4 

14.3 

14.3 

14.2 

14.2 

14.2 

14.1 

14.1 

14.0 

16 

15.4 

15.4 

15.3 

15.3 

15.2 

15.2 

15.2 

15.1 

15.1 

15.0 

17 

16.4 

16.4 

16.3 

16.3 

16.2 

16.2 

16.1 

16.1 

16.0 

16.0 

18 

17.4 

17.4 

17.3 

17.3 

17.2 

17.2 

17.1 

17.1 

17.0 

17.0 

19 

18.4 

18.4 

18.3 

18.3 

18.2 

18.2 

18.1 

18.1 

18.0 

18.0 

20 

19.4 

19.3 

19.3 

19.2 

29.2 

19. 

19.1 

19.0 

19.0 

18.9 

21 

20.4 

20.3 

20.3 

20.2 

20.2 

20. 

20.0 

20.0 

19.9 

19.9 

22 

21.4 

21.3 

21.3 

21.2 

21  1 

21. 

21.0 

21.0 

20.9 

20.9 

23 

22.4 

22.3 

22.3 

22.2 

22.1 

22. 

22.0 

22.0 

21.9 

21.8 

24 

23.4 

23.3 

23.2 

23.2 

23.1 

23. 

23.0 

22.9 

22.9 

22.8 

25 

24.3 

24.3 

24.2 

24.2 

24.1 

24.0 

24.0 

23.9 

23.9 

23.8 

26 

25.3 

25.3 

25.2 

25.1 

25.1 

25.0 

25.0 

24.9 

24.8 

24.8 

27 

26.3 

26.3 

28.2 

26.1 

26.1 

26.0 

25.9 

25.9 

25.8 

2,5.7 

28 

27.3 

27.3 

27.2 

27. 

27.1 

27.0 

26.9 

26.9 

26.8 

26.7 

29 

28.3 

28.3 

28.2 

28. 

28.1 

28.0 

27.9 

27.8 

27.8 

27.7 

30 

29.3 

29.2 

29.2 

29. 

29.0 

29.0 

28.9 

28.8 

28.8 

28.7 

31 

30.3 

30.2 

30.2 

30. 

30.0 

29.9 

29.9 

29.8 

29.7 

29.7 

32 

31.3 

31.2 

31.2 

31. 

31.0 

30.9 

30.9 

30.8 

30.7 

30.6 

33 

32.3 

32.2 

32.1 

32. 

32.0 

31.9 

31.8 

31.8 

31.7 

31.6 

34 

33.3 

33.2 

33.1 

33.0 

33.0 

32.9 

32.8 

32.7 

32.7 

32.6 

35 

34.3 

34.2 

34.1 

34.0 

34.0 

33.9 

33.8 

33.7 

33.6 

33.6 

36 

35.2 

35.2 

35.1 

35.0 

34.9 

34.9 

34.8 

34.7 

34.6 

34.5 

37 

36.2 

36.2 

36.1 

36.0 

35.9 

35.8 

35.8 

35.7 

35.6 

35.5 

38 

37.2 

37.2 

37.1 

37.0 

36.9 

36.8 

36.8 

36.7 

36.6 

36.5 

39 

38.2 

38.1 

38.1 

38.0 

37.9 

37.8 

37.7 

37.6 

37.6 

37.5 

40 

39.2 

39.1 

39.0 

39.0 

38.9 

38.8 

38.7 

38.6 

38.5 

38.5 

41 

40.2 

40.1 

40.0 

39.9 

39.9 

39.8 

39.7 

39.6 

39.5 

39.4 

42 

41.2 

41.1 

41.0 

40.9 

40.8 

40.8 

40.7 

40.6 

40.5 

40.4 

43 

42.2 

42.1 

42.0 

41.9 

41.8 

41.7 

41.7 

41.6 

41.5 

41.4 

44 

43.1 

43.1 

43.0 

42.9 

42.8 

42.7 

42.6 

42.5 

42.5 

42.4 

45 

44.1 

44.0 

44.0 

43.9 

43.8 

43.7 

43.6 

43.5 

43.4 

43.3 

46 

45.1 

45.0 

44.9 

44.9 

44.8 

44.7 

44.6 

44.5 

44.4 

44.3 

47 

46.1 

46.0 

45.9 

45.84 

45.7 

45.7 

45.6 

45.5 

45.4 

45.3 

48 

47.1 

47.0 

46.9 

46.8 

46.7 

46.6 

46.5 

46.5 

46.4 

46.3 

49 

48.1 

48.0 

47.9 

47.8 

47.7 

47.6 

47.5 

47.4 

47.4 

47.3 

50 

49.1 

49.0 

48.9 

48.8 

48.7 

48.6 

48.5 

48.4 

48.3 

48.2 

51 

50.1 

50.0 

49.9 

49.8 

49.7 

49.6 

49.5 

49.4 

49.3 

49.2 

52 

51.0 

50.9 

50.8 

50.7 

50.6 

50.5 

50.4 

50.4 

50.3 

50.2 

53 

52.0 

51.9 

51.8 

51.7 

51.6 

51.5 

51.4 

51.3 

51.2 

51.1 

54 

53.0 

52.9 

52.8 

52.7 

52.6 

52.5 

52.4 

52.3 

52.2 

52.1 

55 

54.0 

53.9 

53.8 

53.7 

53.6 

53.5 

53.4 

53.3 

53.2 

53.1 

56 

55.0 

54.9 

54.8 

54.6 

54.5 

54.4 

54.3 

54.2 

54.1 

54.0 

57 

55.9 

55.8 

55.7 

55.6 

55.5 

55.4 

55.3 

55.2 

55.1 

55.0 

58 

56.9 

56.8 

56.7 

56.6 

56.5 

56.4 

56.3 

56.2 

56.  1 

56.0 

59 

57.9 

57.8 

57.7 

57.6 

57.5 

57.4 

57.3 

57.2 

57.1 

57.0 

60 

58.9 

58.8 

58.7 

58.6 

58.5 

58.3 

58.2 

58.1 

58.0 

57.9 

EXAMINATION   OF   PETROLEUM   THINNERS 


Indication 

TEMPERATURES 

80° 

81° 

82° 

83° 

84° 

85° 

86° 

87° 

88° 

89° 

15 

14.0 

14.0 

13.9 

13.9 

13.8 

13.8 

13.8 

13.7 

13.7 

13.6 

16 

15.0 

15.0 

14.9 

14.9 

14.8 

14.8 

14.8 

14.7 

14.7 

14.6 

17 

15.9 

15.9 

15.8 

15.8 

15.7 

15.7 

15.7 

15.6 

15.6 

15.5 

18 

16.9 

16.9 

16.8 

16.8 

16.7 

16.7 

16.7 

16.6 

16.6 

16.5 

19 

17.9 

17.9 

17.8 

17.8 

17.7 

17.7 

17.6 

17.6 

17.5 

17.5 

20 

18.9 

18.8 

18.7 

18.7 

18.7 

18.6 

18.6 

18.5 

18.5 

18.4 

21 

19.8 

19.8 

19.7 

19.7 

19.6 

19.6 

19.5 

19.5 

19.4 

19.4 

22 

20.8 

20.7 

20.7 

20.6 

20.6 

20.5 

20.5 

20.4 

20.4 

20.3 

23 

21.8 

21.7 

21.6 

21.6 

21.6 

21.5 

21.5 

21.4 

21.3 

21.3 

24 

22.8 

22.7 

22.6 

22.6 

22.5 

22.5 

22.4 

22.4 

22.3 

22.3 

25 

23.7 

23.7 

23.6 

23.6 

23.5 

23.5 

23.4 

23.3 

23.3 

23.2 

26 

24.7 

24.6 

24.6 

24.5 

24.5 

24.4 

24.4 

24.3 

24.2 

24.2 

27 

25.7 

25.6 

25.5 

25.5 

25.5 

25.4 

25.3 

25.3 

25.2 

25.2 

28 

26.7 

26.6 

26.5 

26.5 

26.4 

26.4 

26.3 

26.2 

26.2 

26.1 

29 

27.6 

27.6 

27.5 

27.5 

27.4 

27.3 

27.3 

27.2 

27.1 

27.1 

30 

28.6 

28.6 

28.5 

28.4 

28.4 

28.3 

28.2 

28.2 

28.1 

28.0 

31 

29.6 

29.5 

29.5 

29.4 

29.3 

29.3 

29.2 

29.1 

29.1 

29.0 

32 

30.6 

30.5 

30.4 

30.4 

30.3 

30.2 

30.2 

30.1 

30.0 

30.0 

33 

31.6 

31.5 

31.4 

31.3 

31.3 

31.2 

31.1 

31.1 

31.0 

30.9 

34 

32.5 

32.5 

32.4 

32.3 

32.2 

32.2 

32.1 

32.0 

32.0 

31.9 

35 

33.5 

33.4 

33.3 

33.3 

33.2 

33.1 

33.1 

33.0 

32.9 

32.8 

36 

34.5 

34.4 

34.3 

34.3 

34.2 

34.1 

34.0 

34.0 

33.9 

33.8 

37 

35.5 

35.4 

35.3 

35.2 

35.1 

35.1 

35.0 

34.9 

34.8 

34.8 

38 

36.4 

36.4 

36.3 

36.2 

36.1 

36.0 

36.0 

35.9 

35.8 

35.7 

39 

37.4 

37.3 

37.2 

37.2 

37.1 

37.0 

36.9 

36.8 

36.8 

36.7 

40 

38.4 

38.3 

38.2 

38.1 

38.1 

38.0 

37.9 

37.8 

37.7 

37.7 

41 

39.4 

39.3 

39.2 

39.1 

39.0 

38.9 

38.9 

38.8 

38.7 

38.6 

42 

40.3 

40.3 

40.2 

40.1 

40.0 

39.9 

39.8 

39.8 

39.7 

39.6 

43 

41.3 

41.2 

41.2 

41.1 

41.0 

40.9 

40.8 

40.7 

40.6 

40.6 

44 

42.3 

42.2 

42.1 

42.0 

42.0 

41.9 

41.8 

41.7 

41.6 

41.5 

45 

43.3 

43.2 

43.1 

43.0 

42.9 

42.8 

42.8 

42.7 

42.6 

42.5 

46 

44.2 

44.2 

44.1 

44.0 

43.9 

43.8 

43.7 

43.6 

43.6 

43.5 

47 

45.2 

45.1 

45.0 

45.0 

44.9 

44.8 

44.7 

44.6 

44.5 

44.4 

48 

46.2 

46.1 

46.0 

45.9 

45.8 

45.7 

45.7 

45.6 

45.5 

45.4 

49 

47.2 

47.1 

47.0 

46.9 

46.8 

46.7 

46.6 

46.5 

46.5 

46.4 

50 

48.1 

48.0 

48.0 

47.9 

47.8 

47.7 

47.6 

47.5 

47.4 

47.4 

51 

49.1 

49.0 

48.9 

48.8 

48.7 

48.6 

48.6 

48.5 

48.4 

48.3 

52 

50.1 

50.0 

49.9 

49.8 

49.7 

49.6 

49.5 

49.4 

49.4 

49.3 

53 

51.0 

50.9 

50.9 

50.8 

50.7 

50.6 

50.5 

50.4 

50.3 

50.2 

54 

52.0 

51.9 

51.8 

51.7 

51.6 

51.5 

51.4 

51.3 

51.3 

51.2 

55 

53.0 

52.9 

52.8 

52.7 

52.6 

52.5 

52.4 

52.3 

52.2 

52.1 

56 

53.9 

53.8 

53.7 

53.6 

53.5 

53.4 

53.4 

53.3 

53.2 

53.1 

57 

54.9 

54.8 

54.7 

54.6 

54.5 

54.4 

54.3 

54.2 

54.1 

54.0 

58 

55.9 

55.8 

55.7 

55.6 

55.5 

55.4 

55.3 

55.2 

55.1 

55.0 

59 

56.8 

56.7 

56.6 

56.5 

56.4 

56.3 

56.2 

56.1 

56.0 

55.9 

60 

57.8 

57.7 

57.6 

57.5 

57.4 

57.3 

57.2 

57.1 

57.0 

56.9 

10         PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

TABLE  II 
7.  Specific  gravity  corresponding  to  degrees  Baume  at  -Q0    '      '       ' 

141.5 
Formula    Sp.  Gr.  =  m.6+B 

TENTHS  OF  DEGREES 


Degrees 

Baum6 

0 

1 

2 

3 

10 

1.0000 

.9993 

.9986 

.9979 

.9972 

.9965 

.9958 

.9951 

.9944 

.9937 

11 

.9930 

.9923 

.9916 

.9909 

.9902 

.9895 

.9881 

.9874 

.9868 

12 

.9861 

.9854 

.9847 

.9840 

.9833 

.9826 

^9820 

.9813 

.9806 

.9799 

13 

.9792 

.9786 

.9779 

.9772 

.9765 

.9759 

.9752 

.9745 

.9738 

.9732 

14 

.9725 

.9718 

.9712 

.9705 

.9692 

.9685 

.9679 

.9672 

.9665 

15 

.9659 

.9652 

.9646 

.9639 

.9632 

.9626 

.9619 

.9613 

.9606 

.9600 

16 

.9593 

.9587 

.9580 

.9574 

.9567 

.9561 

.9554 

.9548 

.9542 

.9535 

17 

.9529 

.9522 

.9516 

.9509 

.9503 

.9497 

.9490 

.9484 

.9478 

.9471 

18 

.9465 

.9459 

.9452 

.9446 

.9440 

.9433 

.9427 

.9421 

.9415 

.9408 

19 

.9402 

.9396 

.9390 

.9383 

.9377 

.9371 

.9365 

.9359 

.9352 

.9346 

'  20 

.9340 

.9334 

.9328 

.9322 

.9315 

.9309 

.9303 

.9297 

.9291 

.9285 

21 

.9279 

.9273 

.9267 

.9260 

.9254 

.9248 

.9242 

.9236 

.9230 

.9224 

22 

.9218 

.9212 

.9206 

.9200 

.9194 

.9188 

.9182 

.9176 

.9170 

.9165 

23 

.9159 

.9153 

.9147 

.9141 

.9135 

.9129 

.9123 

.9117 

.9111 

.9106 

24 

.9100 

.9094 

.9088 

.9082 

.9076 

.9071 

.9065 

.9059 

.9053 

.9047 

25 

.9042 

.9036 

.9030 

.9024 

.9018 

.9013 

.9007 

.9001 

.8996 

.8990 

26 

.8984 

.8978 

.8973 

.8967 

.8961 

.8956 

.8950 

.8944 

.8939 

.8933 

27 

.8927 

.8922 

.8916 

.8911 

.8905 

.8899 

.8894 

.8888 

.8883 

.8877 

28 

.8871 

.8866 

.8860 

.8855 

.8849 

.8844 

.8838 

.8833 

.8827 

.8822 

29 

.8816 

.8811 

.8805 

.8800 

.8794 

.8789 

.8783 

.8778 

.8772 

.8767 

30 

.8762 

.8756 

.8751 

.8745 

.8740 

.8735 

.8729 

.8724 

.8718 

.8713 

31 

.8708 

.8702 

.8697 

.8692 

.8686 

.8681 

.8676 

.8670 

.8665 

.8660 

32 

.8654 

.8649 

.8644 

.8639 

.8633 

.8628 

.8623 

.8618 

.8612 

.8607 

33 

.8602 

.8597 

.8591 

.8586 

.8581 

.8576 

.8571 

.8565 

.8560 

.8555 

34 

.8550 

.8545 

.8540 

.8534 

.8529 

.8524 

.8519 

.8514 

.8509 

.8504 

35 

.8498 

.8493 

.8488 

.8483 

.8478 

.8473 

.8468 

.8463 

.8458 

.8453 

36 

.8448 

.8443 

.8438 

.8433 

.8428 

.8423 

.8418 

.8413 

.8408 

.8403 

37 

.8398 

.8393 

8388 

.8383 

.8378 

.8373 

.8368 

.8363 

.8358 

.8353 

38 

.8348 

.8343 

.8338 

.8333 

.8328 

.8324 

.8319 

.8314 

.8309 

.8304 

.8299 

.8294 

.8289 

.8285 

.8280 

.8275 

.8270 

.8265 

.8260 

.8256 

40 

.8251 

.8246 

.8241 

.8236 

.8232 

.8227 

.8222 

.8217 

.8212 

.8208 

41 

.8203 

.8198 

.8193 

.8189 

.8184 

.8179 

.8174 

.8170 

.8165 

.8160 

42 

.8156 

.8151 

.8146 

.8142 

.8137 

.8132 

.8128 

.8123 

.8118 

.8114 

43 

.8109 

.8104 

.SUM) 

.8095 

.8090 

.8086 

.8081 

.8076 

.8072 

.8067 

44 

.8063 

.8058 

.8053 

.8049 

.8044 

.8040 

.8035 

.8031 

.8026 

.8022 

45 

.8017 

.8012 

.8008 

.8003 

.7999 

.7994 

.7990 

.7985 

.7981 

.7976 

46 

.7972 

.7967 

.7963 

.7958 

.7954 

.7949 

.7945 

.7941 

.7936 

.7932 

47 

.7927 

.7923 

.7918 

.7914 

.7909 

.7905 

.7901 

.7896 

.7892 

.7887 

48 

.7883 

.7879 

.7874 

.7870 

.  7865 

.7861 

.7857 

.7852 

.7848 

.7844 

49 

.7839 

.7835 

.7831 

.7826 

.7822 

.7818 

.7813 

.7809 

.7805 

.7800 

50 

.7796 

.7792 

.7788 

.7783 

.7779 

.7775 

.7770 

.7766 

.7762 

.7758 

51 

.7753 

.7749 

.7745 

.7741 

.7736 

.7732 

.7728 

.7724 

.7720 

.7715 

52 

.7711 

.7707 

.7703 

.7699 

.7694 

.7690 

.7686 

.7682 

.7678 

.7674 

53 

.7669 

.7665 

.7661 

.7657 

.7653 

.7649 

.7645 

.7640 

.7636 

.7632 

54 

.7628 

.7624 

.7620 

.7616 

.7012 

.7608 

.7603 

.7599 

.7595 

.7591 

55 

.7587 

.7583 

.7579 

.7575 

.7571 

.7567 

.7563 

.7559 

.7555 

.7551 

56 

.7547 

.7543 

.7539 

.7535 

.7531 

.7527 

.7523 

.7519 

.7515 

.7511 

57 

.7507 

.7503 

.7499 

.  7495 

.7491 

.7487 

.7483 

.7479 

.  7475 

.7471 

58 

.7467 

.7463 

.7459 

.7455 

.7451 

.7417 

.7143 

.7440 

.7436 

.7432 

59 

.7428 

.7424 

.7420 

.7416 

.7412 

.7408 

.7405 

.7401 

.7397 

.7393 

EXAMINATION   OF   PETROLEUM   THINNERS 


11 


TENTHS  OF  DEGREES 


Degrees 

Baume 

0 

60 

7389 

.7385 

.7381 

.7377 

.7374 

.7370 

.7366 

.7362 

.7358 

.7354 

til 

>351 

.7347 

.7343 

.7339 

.7335 

.  7332 

.7328 

.7324 

.7320 

.7316 

02 

.7313 

.7309 

.7305 

.7301 

.7298 

.7294 

.7290 

.7286 

.7283 

.7279 

03 

.7275 

.7271 

.7268 

.7264 

.7260 

.7256 

.7253 

.7249 

.7245 

.7242 

64 

.7238 

.7234 

.7230 

.7227 

.7223 

.7219 

.7216 

.7212 

.7208 

.7205 

65 

.7201 

.7197 

.7194 

.7190 

.7186 

.7183 

.7179 

.7175 

.7172 

.7168 

66 

.7165 

.7161 

.7157 

.7154 

.7150 

.7146 

.7143 

.7139 

.7136 

.7132 

67 

.7128 

.7125 

.7121 

.7118 

.7114 

.7111 

.7107 

.7103 

.7100 

.7096 

68 

.7093 

.7089 

.7086 

.7082 

.7079 

.7075 

.7071 

.7068 

.7064 

.7061 

69 

.7057 

.7054 

.7050 

.7047 

.7043 

.7040 

.7036 

.7033 

.7029 

.7026 

70 

.7022 

.7019 

.7015 

.7012 

.7008 

.7005 

.7001 

6998 

.6995 

.6991 

71 

.6988 

.6984 

.6981 

.6977 

.6974 

.6970 

.6967 

.6964 

.6960 

.6957 

72 

.6953 

.6950 

.6946 

.6943 

.6940 

.6936 

.6933 

.6929 

.6926 

.6923 

73 

.6919 

.6916 

.6912 

.6909 

.6906 

.6902 

.6899 

.6896 

.6892 

6889 

74 

.6886 

.6882 

.6879 

.6876 

.6872 

.6866 

.6862 

.6859 

^6856 

75 

.6852 

.6849 

.6846 

.6842 

.6839 

.6836 

.6832 

.6829 

.6826 

.6823 

76 

.6819 

.6816 

.6813 

.6809 

.6806 

.6803 

.6800 

.6796 

.6793 

.6790 

77 

.6787 

.6783 

.6780 

.6777 

.6774 

.6770 

.6767 

.6764 

.6761 

.6757 

78 

.6754 

.6751 

.6748 

.6745 

.6741 

.6738 

.6735 

.6732 

.6728 

.6725 

79 

.6722 

.6719 

.6716 

.6713 

.6709 

.6706 

.6703 

.6700 

.6697 

.6693 

80 

.6690 

.6687 

.6684 

.6681 

.6678 

.6675 

.6671 

.6668 

.6665 

.6662 

81 

.6659 

.0056 

.  0053 

.6649 

.6646 

.6643 

.6640 

.6637 

.6634 

.6631 

82 

.6628 

ISO!'.-) 

.6021 

.6618 

.6615 

.6612 

.  6009 

.6606 

.6603 

.6600 

83 

.6597 

.0594 

.6591 

.6588 

.6584 

.6581 

.6578 

.6575 

.6572 

.6569 

84 

.6566 

.6563 

.6560 

.6557 

.6554 

.6551 

.6548 

.6545 

.6542 

.6539 

85 

.6536 

.6533 

.6530 

.6527 

.6524 

.6521 

.6518 

.6515 

.6512 

.6509 

86 

.6506 

.6503 

.6500 

.6497 

.6494 

.6491 

.6488 

.6485 

.6482 

.6479 

87 

.6476 

.6473 

.6470 

.6467 

.6464 

.6461 

.6458 

.6455 

.6452 

.6449 

.6446 

.6444 

.6441 

.6438 

.6435 

.6432 

.6429 

.6426 

.6423 

.6420 

89 

.6417 

.6414 

.6411 

.6409 

.6406 

.6403 

.6400 

.6397 

.6394 

.6391 

90 

.6388 

.6385 

.6382 

.6380 

.6377 

.6374 

.6371 

.6368 

.6365 

.6362 

91 

.6360 

.0357 

.  6354 

.6351 

.6348 

.6345 

.6342 

.6340 

.6337 

.6334 

92 

.6331 

.0328 

.6325 

!0323 

.6320 

.6317 

.6314 

.6311 

.6309 

.6306 

93 

.6303 

.  6300 

.6297 

.  6294 

.6292 

.6289 

.6286 

.6283 

.6281 

.6278 

94 

.6275 

.6272 

.6269 

.6267 

.6264 

.6261 

.6258 

.6256 

.6253 

.6250 

95 

.6247 

.6244 

.6242 

.6239 

.6236 

.6233 

.6231 

.6228 

.6225 

.6223 

96 

.6220 

.6217 

.6214 

.6212 

.6209 

.  0200 

.6203 

.6201 

.6198 

.6195 

97 

.6193, 

.OHIO 

.6187 

.6184 

.6182 

.6179 

.6176 

.6174 

.6171 

.6168 

98 

.6166 

.6163 

.6160 

.6158 

.6155 

.6152 

.6150 

.6147 

.6144 

.6141 

99 

.6139 

.6136 

.6134 

.6131 

.6128 

.6126 

.6123 

.6120 

.6118 

.6115 

12         PAINT   VEHICLES,   JAPANS  AND  VARNISHES 


TABLE  HA 

8.  Equivalent  pounds  per  gallon  to  degrees  Baume  at  60°  F. 
TENTHS  OF  DEGREES 


Degrees 

Baume 

10 

8.331 

8.325 

8.319 

8.314 

8.308 

8.302 

8.296 

8.290 

8.284 

8.279 

11 

8.273 

8.267 

8.261 

8.255 

8.249 

8.244 

8.238 

8.232 

8.226 

8.221 

12 

8.215 

8.209 

8.204 

8.198 

8.192 

8.186 

8.181 

8.175 

8.169 

8.104 

13 

8.158 

8.153 

8.147 

8.141 

8.135 

6.130 

8.124 

8.119 

8.113 

8.108 

14 

8.102 

8.096 

8.091 

8.085 

8.079 

8.074 

8.069 

8.064 

8.058 

8.052 

15 

8.047 

8.041 

8.036 

8.030 

8.024 

8.019 

8.014 

8.009 

8.003 

7.998 

16 

7.992 

7.987 

7.981 

7.976 

7.970 

7.965 

7.959 

7.954 

7.949 

7.944 

17 

7.939 

7.933 

7.928 

7.922 

7.917 

7.912 

7.906 

7.901 

7.896 

7.890 

18 

7.885 

7.880 

7  874 

7.869 

7.864 

7.859 

7.854 

7.849 

7.844 

7.838 

19 

7.833 

7.828 

7.823 

7.817 

7.812 

7.807 

7.802 

7.797 

7.791 

7.786 

20 

7.781 

7.776 

7.771 

7.766 

7.760 

7.755 

7.750 

7.745 

7.740 

7.735 

21 

7.730 

7.725 

7.720 

7.715 

7.710 

7.705 

7.700 

7.695 

7.690 

7.685 

22 

7.680 

7.675 

7.670 

7.  605 

7  .  6GO 

7.655 

7.650 

7.645 

7.640 

7.635 

23 

7.630 

7.625 

7.620 

7.615 

7.610 

7.605 

7.600 

7.595 

7.590 

7.586 

24 

7.581 

7.576 

7.571 

7.566 

7.561 

7.557 

7.552 

7.547 

7.542 

7.537 

25 

7.533 

7.528 

7.523 

7.518 

7.513 

7.509 

7.504 

7.499 

7.495 

7.490 

26 

7.485 

7.480 

7.475 

7.471 

7.465 

7.461 

7.456 

7.451 

7.447 

7.442 

27 

7.437 

7.433 

7.428 

7.424 

7.419 

7.414 

7.410 

7.405 

7.400 

7.395 

28 

7.390 

7.386 

7.381 

7.377 

7.372 

7.368 

7.363 

7.359 

7.354 

7.350 

29 

7.345 

7.340 

7.335 

7.331 

7.326 

7.322 

7.318 

7.313 

7.308 

7.304 

30 

7.300 

7.295 

7.290 

7.285 

7.281 

7.277 

7.272 

7.268 

7.263 

7.259 

31 

7.255 

7.250 

7.245 

7.241 

7.236 

7.232 

7.228 

7.223 

7.219 

7.215 

32 

7.210 

7.205 

7.201 

7.197 

7.192 

7.188 

7.184 

7.180 

7.175 

7.170 

33 

7.166 

7.162 

7.157 

7.153 

7.149 

7.145 

7.141 

7.136 

7.131 

7.127 

34 

7.123 

7.119 

7.115 

7.110 

7.106 

7.101 

7.097 

7.093 

7.089 

7.085 

35 

7.080 

7.076 

7.071 

7.067 

7.063 

7.059 

7.055 

7.051 

7.046 

7.042 

36 

7.038 

7.034 

7.030 

7.026 

7.021 

7.017 

7.013 

7.009 

7.005 

7.001 

37 

6.996 

6.992 

6.988 

6.984 

6.980 

6.976 

6.971 

6.967 

6.963 

6.959 

38 

6.955 

6.951 

6.946 

6.942 

6.938 

6.935 

6.931 

6.926 

6.922 

6.918 

39 

6.914 

6.910 

6.906 

6.902 

6.898 

6.894 

6.890 

6.886 

6.881 

6.878 

40 

6.874 

6.870 

6.866 

6.861 

6.858 

6.854 

6.850 

6.846 

6.841 

6.838 

41 

6.834 

6.830 

6.826 

6.822 

6.818 

6.814 

6.810 

6.806 

6.802 

6.798 

42 

6.795 

6.791 

6.786 

6.783 

6.779 

6.775 

6.771 

6.767 

6.763 

6.760 

43 

6.756 

6.751 

6.748 

6.744 

6.740 

6.736 

6.732 

6.728 

6.725 

6.721 

44 

6.717 

6.713 

6.709 

6.706 

6.701 

6.698 

6.694 

6.691 

6.686 

6.683 

45 

6.679 

6.675 

6.671 

6.667 

6.664 

6.660 

6.656 

6.652 

6.649 

6  645 

46 

6.641 

6.637 

6.634 

6.630 

6.626 

6.623 

6.619 

6.616 

6.611 

6.608 

47 

6.604 

6.601 

6.596 

6.593 

6.589 

6.586 

6.582 

6.578 

6.575 

6.571 

48 

6.567 

6.564 

6.560 

6.556 

6.552 

6.549 

6.546 

6.542 

6.538 

6.535 

49 

6.531 

6.527 

6.524 

6.520 

6.517 

6.513 

6.509 

6.506 

6.502 

6.498 

50 

6.495 

6.492 

6.488 

6.484 

6.481 

6.477 

6.473 

6.470 

6.467 

6.463 

51 

6.459 

6.456 

6.452 

6.449 

6.445 

6.442 

6.438 

6.435 

6.432 

6.427 

52 

6.424 

6.421 

6.417 

6.414 

6.410 

6.407 

6.403 

6.400 

6.397 

6.393 

53 

6.389 

6.386 

6.382 

6.379 

6.376 

6.372 

6.369 

6.365 

6.362 

6.358 

54 

6.355 

6.352 

6.348 

6.345 

6.342 

6.338 

6.334 

6.331 

6.327 

6.324 

55 

6.321 

6.317 

6.314 

6.311 

6.307 

6.304 

6.301 

6.297 

6.294 

6.291 

56 

6.287 

6.284 

6.281 

6.277 

6.274 

6.271 

6.267 

6.264 

6.261 

6.257 

57 

6.254 

6.251 

6.247 

6.244 

6.241 

6.237 

6.234 

6.231 

6.227 

6.224 

58 

6.221 

6.217 

6.214 

6.211 

6.207 

6.204 

6.201 

6.198 

6.195 

6.191 

59 

6.188 

6.185 

6.182 

6.178 

6.175 

6.172 

6.169 

6.166 

6.162 

6.159 

EXAMINATION   OF  PETROLEUM   THINNERS          13 


TENTHS  OF  DEGREES 


Degrees 

Baume 

60 

6.156 

6.152 

6.149 

6.146 

6.143 

6.140 

6.137 

6.133 

6.130 

6.  127 

61 

6.  124 

6  121 

6.117 

6.114 

6.111 

6.108 

6.105 

6.102 

6.098 

6  095 

62 

6.092 

6.089 

6.086 

6.082 

6.080 

6.077 

6.073 

6.070 

6.067 

6^064 

63 

6.061 

6.057 

6.055 

6.052 

6.048 

6.045 

6.042 

6.039 

6.036 

6  033 

61 

6.030 

6.027 

6.023 

6.021 

6.017 

6.014 

6.012 

6.008 

6.005 

6.002 

65 

5.999 

5.996 

5.993 

5.990 

5.987 

5.984 

5.981 

5.977 

5  975 

5.972 

66 

5.969 

5.966 

5.962 

5.960 

5.957 

5.953 

5.951 

5.948 

5.945 

5.942 

67 

5.938 

5.935 

5.933 

5.930 

5.927 

5.924 

5.921 

5.918 

5.915 

5.912 

68 

5.909 

5.903 

5.903 

5.900 

5.898 

5.894 

5.891 

£  .  888 

5.885 

5.883 

69 

5.879 

5.877 

5.873 

5.871 

5.868 

5.865 

5.862 

5.859 

3.856 

5.853 

70 

5.850 

5.848 

5.844 

5.842 

5.838 

5.836 

5.833 

5.830 

5.828 

5.824 

71 

5.822 

5.818 

5.816 

5.813 

5.810 

5.807 

5.804 

5.802 

5.798 

5.796 

•      72 

5.793 

5.790 

5.787 

5.781 

5.782 

5.778 

5.776 

5.773 

5.770 

5.768 

73 

5.764 

5.762 

5.758 

5.756 

5.753 

5.750 

5.748 

5.745 

5.742 

5.739 

74 

5.737 

5.733 

5.731 

5.728 

5.725 

5.723 

5.720 

5.717 

5.714 

5.712 

75 

5.708 

5.706 

5.703 

5.700 

5.698 

5.695 

5.692 

5.689 

5.687 

5.684 

76 

5.681 

5.678 

5.676 

5.673 

5.670 

5.668 

5.665 

5.662 

5.659 

5.657 

77 

5.654 

5.651 

5.648 

5.646 

5.643 

5.640 

5.638 

5.635 

5.633 

5.629 

78 

5.627 

5.624 

5.622 

5.619 

5.616 

5.613 

5.611 

5.608 

5.605 

5.603 

79 

5.600 

5.597 

5.595 

5.593 

5.589 

5.587 

5.584 

5.582 

5.579 

5.576 

80 

5.573 

5.571 

5.568 

5.566 

5.563 

5.561 

5.558 

5.555 

5.553 

5.550 

81 

5.548 

5.545 

5.543 

5.540 

5.537 

5.534 

5.532 

5.529 

5.527 

5.524 

82 

5.522 

5.519 

5.516 

5.513 

5.511 

5.508 

5.506 

5.503 

5.501 

5.498 

83 

5.496 

5.493 

5.491 

5.488 

5.485 

5.483 

5.480 

5.478 

5.475 

5.473 

81 

5.470 

5.468 

5.465 

5.463 

5.460 

5.458 

5.455 

5.453 

5.450 

5.448 

85 

5.445 

5.443 

5.440 

5.438 

5.435 

5.433 

5.430 

5.428 

5.425 

5.423 

86 

5.420 

5.418 

5.415 

5.413 

5.410 

5.408 

5.405 

5.403 

5.400 

5.398 

87 

5.395 

5.393 

5.390 

5.388 

5.385 

5.383 

5.380 

5.378 

5.375 

5.373 

88 

5.370 

5.368 

5.363 

5  .  363 

5.361 

5.358 

5.356 

5.353 

5.351 

5.349 

89 

5.346 

5.344 

5.341 

5.339 

5.337 

5.334 

5.332 

5.329 

5.327 

5.324 

90 

5.322 

5.319 

5.317 

5.315 

5.313 

5.310 

5.308 

5.305 

5.303 

5.300 

91 

5.299 

5.296 

5.294 

5.291 

5.289 

5.286 

5.284 

5.282 

5.279 

5.277 

92 

5.274 

5.272 

5.269 

5.268 

5.265 

5.263 

5.260 

5.258 

5.256 

5.254 

93 

5.251 

5.249 

5.246 

5.244 

5.242 

5.239 

5.237 

5.234 

5.233 

5.230 

94 

5.228 

5.225 

5.223 

5.221 

5.219 

5.216 

5.214 

5.212 

5.209 

5.207 

95 

5.204 

5.202 

5.200 

5.  198 

5.195 

5.193 

5.191 

5.189 

5.186 

5.184 

96 

5.182 

5.179 

5.177 

5.175 

5.173 

5.170 

5.168 

5.166 

5.164 

5.161 

97 

5.159 

5.157 

5.154 

5.152 

5.150 

5.148 

5.145 

5.144 

5.141 

5.139 

98 

5.137 

5.134 

5.132 

5.130 

5.128 

5.125 

5.124 

5.121 

5.119 

5.116 

99 

5.114 

5.112 

5.110 

5.108 

5.105 

5.104 

5.101 

5.099 

5.097 

5.094 

CHAPTER  II 

EXAMINATION   OF  PETROLEUM  THINNERS   (Continued) 

9.  Composition.     In   the   distillation   of  petroleum 
thinners,  one  has  to  deal  with  a  solvent  composed  of 
a  large  number  of  compounds  or  series  of  compounds, 
the  members  of  which  so  closely  resemble  each  other  in 
their  physical  and  chemical  properties  that  absolute 
differentiation  by  any  simple  means  is  very  difficult 
and  practically  impossible.     Distillation  is  the  simplest 
method  of  securing  an  approximate  separation. 

The  success  of  this  method  depends  chiefly  on  a 
close  adjustment  and  control  of  the  distilling  tem- 
perature. 

10.  Difficulties      encountered      in      the      ordinary 
methods.     The    use    of    the    Engler    distilling    flask 
heated  with  a  Bunsen  flame  is  too  well  known  to  need 
description  here,  but  connected  with  its  use  are  many 
difficulties  that  are  often  not  appreciated.     The  con- 
tinual wavering  of  the  flame,   even  when   carefully 
screened  from  air  currents,  the  fluctuation  of  the  gas 
pressure,  and  the  condensation  of  the  vapors  in  the 
neck  of  the  flask  which  cause  them  to   "  crack  "  or 
become  partially  decomposed  when  dropping  on  the 
hot  liquid  below,  cause  irregularity  in  the  rate  of  dis- 
tillation.    Duplication  of  results,  whether  by  the  same 
operator  or  others,   does  not,   therefore,    yield   frac- 
tions that  are  alike  either  in  quantity  or  quality.     The 
same  is  true  when  the  Engler  flask  is  immersed  in  an 
oil  bath,  though  not  to  such  a  great  extent. 

14 


EXAMINATION   OF  PETROLEUM   THINNERS          15 

Experience  has  taught  the  author  that  petroleum 
thinners,  as  produced  at  the  present  tune,  do  not  run 
sufficiently  uniform  to  be  satisfactory  at  all  times  in 
the  manufacture  of  the  highly  specialized  enamels, 
paints,  and  varnishes  used  in  the  various  manufac- 
turing industries. 

The  ordinary  methods  of  distillation  having  proven 
inadequate  for  the  correct  valuation  of  such  thinners, 
the  author  began  a  search  for  a  more  careful  and 
suitable  means  of  procedure.  The  apparatus  here 
described  has  proven  very  satisfactory  and  is  the 
method  used  in  the  Petroleum  Laboratory  of  the 
Bureau  of  Mines.1 

11.  Apparatus    used.     The   apparatus    consists   es- 
sentially of  two  pear-shaped  halves  of  heat-resisting 
material  inclosing  and  closely  fitting  a  standard  Engler 
flask.    The  halves  have  imbedded  on  their  inner  sur- 
face  a   metal-resistance  wire  wound  back  and  forth 
for  conducting  an  electric  current  which  is  the  heating 
element.     The  heated  wire  warms  the  flask  and  con- 
tents, causing  the  distillation  to  proceed  quietly  and 
uniformly.    Very  close  duplicates  can  be  obtained  by 
this  method. 

12.  Construction  of  the  heater.     The  body  of  the 
heater  is  composed  of  100  parts  by  weight  of  powdered 
magnesia,   100  parts  of  powdered  silica,  40  parts  of 
shredded  asbestos,  and  10  parts  freely  soluble  pow- 
dered sodium  silicate,  or  a  solution  of  40°  Be.  water 
glass,   containing  an  equivalent   quantity  of  sodium 
silicate.    The  above  components  are  first  thoroughly 
mixed  and  then  made  into  a  paste  with  a  10  per  cent 
solution  of  magnesium  chloride. 

1  Original  Communications,  Eighth  International  Congress  of  Ap- 
plied Chemistry,  Section  IV,  page  15. 


1G         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

The  form  for  the  mold  is  made  by  turning  from 
a  block  of  soft  pine  a  model  having  the  same  size  and 
form  as  that  of  the  standard  Engler  flask,  described 
below,  the  bulb  and  neck  being  turned  in  one  piece. 
Saw  the  model  into  halves  from  top  to  bottom.  Hol- 
low out  the  neck  and  bulb  to  form  a  shallow  dipper, 
making  the  cavity  about  1  cm.  deep  and  leaving  the 
rim  about  3  mm.  thick.  Drill  holes  the  size  of  small 
wire  brads  1  cm.  apart  and  3  mm.  below  the  edge 
of  the  rim  of  the  dipper  and  along  the  neck.  Insert 
brads  or  small  nails  from  the  inside  through  the  holes, 
allowing  the  points  to  project  about  3  mm.,  as  shown 
in  Fig.  1. 


ci 


FIG.  1.  —  CONSTRUCTION  OF  HEATER 

A  standard  Engler  flask  of  the  capacity  and  dimen- 
sions specified  in  Fig.  2  should  be  used  in  designing 
the  model,  and  particular  emphasis  should  be  used  in 
specifying  these  flasks  when  ordering  from  the  sup- 
ply house,  as  the  so-called  Engler  flasks,  listed  in  most 
catalogues,  vary  widely  from  the  specified  dimensions. 


EXAMINATION  OF   PETROLEUM  THINNERS 


17 


13.  Wiring.  Any  high-resistance  wire  can  be  used, 
but  a  No.  24  nickel-chromium  wire  gives  the  most 
satisfactory  results.  The  manner  of  wiring  the  halves 
of  the  heater  is  of  prime  importance.  Winding  the 
wires  equidistant  from  one  another  from  the  bottom 
of  the  flask  to  the  top  of  the  neck  develops  too  great 


FIG.  2.  —  ENGLER  FLASK 

a  heat  in  the  neck,  thus  superheating  the  vapors,  caus- 
ing them  to  "  crack."  Leaving  the  neck  entirely 
unwound  causes  the  vapors  to  condense,  resulting  in 
partial  decomposition  or  cracking  of  the  thinner.  The 
manner  of  wiring  shown  in  Fig.  1  gives  a  fairly  uni- 
form temperature  from  the  bottom  of  the  flask  to  the 
side  arm  where  the  vapors  are  given  off.  In  the  case 
of  the  unprotected  Engler  flask,  where  there  is  direct 


18         PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

heating  by  the  flame  or  where  the  flask  is  immersed 
in  an  oil  bath,  the  temperature  of  the  vapors  at  the 
side  arm  may  be  from  20-40°  C.  cooler  than  the 
temperature  of  the  boiling  liquid. 

The  method  of  winding  used  by  the  author  has 
11  cross  wires  on  the  bulb,  5  cross  wires  on  the  neck 
below  the  side  arm,  and  4  cross  wires  on  the  neck 
above  the  side  arm,  making  a  total  of  20  wires  on  each 
half  of  the  heater.  The  relation  of  wiring  to  the  tem- 
perature at  the  different  parts  of  the  flask  can  readily 
be  ascertained  by  placing  thermometers  at  different 
levels  during  the  distillation  of  a  liquid  of  constant 
boiling  point. 

After  greasing  the  convex  surface  of  the  mold  to 
prevent  the  paste  from  sticking  to  it,  wind  the  resist- 
ance wire  back  and  forth  as  shown  in  Fig.  1,  tying  the 
wire  in  place  with  asbestos  cord  and  fastening  the  ends 
of  the  wire  to  binding  posts  projecting  at  convenient 
positions.  Lay  the  wired  mold,  convex  side  up,  on  a 
smooth  surface  covered  with  a  sheet  of  paper  and 
apply  the  freshly  prepared  paste  to  the  desired  thick- 
ness, usually  about  one-half  inch. 

14.  Drying.    After  allowing  the  paste  to  set,  pref- 
erably over  night  in  a  cool  place,  remove  the  brads 
from  the  inside  of  the  mold  and  carefully  loosen  the 
mold  from  the  shell  thus  formed.     The  heater  is  then 
dried  in  an  oven  at  50°  C.  for  about  24  hours,  after 
which  it  is  slowly  heated  up  to  200°  C.  to  remove  the 
last  traces  of  moisture.    The  drying  must  be  care- 
fully   carried    out    so    as    to   prevent    cracking   and 
warping.     The  completed  half  of  the  heater  is  shown 
in  Fig.  1  b. 

15.  Temperature   control.     The  temperature  being 
controlled  by  the  current,  it  is  necessary  to  have  some 


EXAMINATION   OF   PETROLEUM   THINNERS 


19 


form  of  rheostat.  The  cheapest  type  having  the 
greatest  range  of  resistance  is  the  water  rheostat. 
The  one  used  by  the  author  is  constructed  as  follows: 
An  ordinary  three-gallon  stone  jar  is  filled  with  a  very 
dilute  solution  of  sulphuric  acid.  The  electrodes  are 
of  sheet  lead,  one  being  in  the  shape  of  an  "L,"  which 
is  stationary,  the  other  triangular  and  suspended 
from  a  windlass  which  is  provided  with  a  brake. 

The  two  halves  of  the  heater,  the  rheostat  and  an 
ammeter,  are  connected  in  series  with  the  lighting  cir- 
cuit (see  Fig.  3).  The  current  and  consequently  the 


FIG.  3 

temperature  is  controlled  by  lowering  or  raising  the 
triangular  electrode.  The  range  of  current  for  most 
thinners  is  from  2  amps,  at  the  beginning  to  3.5-4.0 
amps,  at  the  end  of  the  distillation. 


20         PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

The  heater  should  be  given  a  thorough  test  before 
being  accepted  as  satisfactory.  It  may  be  necessary 
to  make  changes  in  the  manner  of  wiring  such  as  chang- 
ing the  number  of  turns  of  wire  on  the  neck.  It  is 
essential  to  have  the  temperature  of  the  vapors  at  the 
neck  in  close  agreement  with  the  temperature  of  the 
boiling  liquid.  There  should  not  be  a  difference  of 
over  three  degrees  Centigrade  between  the  vapors 
and  the  boiling  liquid.  The  rate  of  distillation  should 
be  about  1  c.c.  per  minute.  This  is  best  observed  by 
using  two  or  more  thermometers  during  the  trial 
test  while  the  distillation  proceeds  as  previously  de- 
scribed. 

16.  Bumping.     The  tendency  of  the  liquid  to  bump 
in  an  electrically  heated  flask  is  greater  than  when 
the  flask  is  heated  by  a  gas  flame.     This  is  best  pre- 
vented by  using  a  fresh  boiling  stone  such  as  a  piece 
of  pumice  with  e&ch  distillation. 

Standard  Method  of  Distillation  Adopted  by  American 
Society  for  Testing  Materials  (1917) 

17.  Apparatus.     The   general   arrangement    of   the 
apparatus  is  shown  in  Fig.  4. 

18.  Flask.    The  flask  used  shall  be  the  Standard 
Engler  flask,  as   described   in   the   various   standard 
works  upon  petroleum,  such  as  Redwood,  Holde,  etc. 

"  Engler  employs  a  globular  flask  6.5  cm.  in  diam- 
eter, with  a  cylindrical  neck  1.6  cm.  in  internal  diam- 
eter and  15  cm.  in  length,  from  the  side  of  which  a 
vapor  tube  10  cm.  in  length  extends  at  an  angle  of  75 
degrees  downwards  to  the  condenser.  The  junction 
of  the  vapor  tube  with  the  neck  of  the  flask  should  be 
9  cm.  above  the  surface  of  the  oil  when  the  flask  con- 
tains its  charge  of  100  c.c.  of  oil.  The  observance  of 


EXAMINATION   OF   PETROLEUM   THINNERS 


21 


the  prescribed  dimensions  is  considered  essential  to 
the  attainment  of  uniformity  of  results."  l 

The  flask  shall  be  supported  in  a  ring  of  asbestos 
having  an  opening  lj  in.  in  diameter  in  its  center. 


FlG.  4. — 'DISTILLATION  APPARATUS 

The  flask,  burner,  etc.,  shall  be  surrounded  by  a 
shield. 

19.  Condenser.  The  condenser  shall  consist  of  a 
tube  of  thin  brass  of  \  in.  internal  diameter,  22  in.  in 
length,  set  at  an  angle  of  75  degrees  with  the  flask  and 
surrounded  by  a  water  jacket  of  the  trough  type. 

1  Redwood,  3d  edition,  Vol.  2,  page  205  (1913). 


22         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

The  lower  end  of  the  condenser  shall  be  cut  off  at  an 
acute  angle  and  shall  be  curved  down  for  a  length  of 
3  in.,  so  as  to  project  at  least  f  in.  into  the  100-c.c. 
cylinder  used  as  a  receiver. 

A  cover  (pasteboard)  should  be  placed  over  the  top 
of  the  cylinder  and  surrounding  the  condenser  tube. 

20.  Thermometer.  The  thermometer  used  shall 
conform  to  the  following  specifications: 

The  thermometer  shall  be  graduated  from  0  to 
400°  C.  in  intervals  of  1°  C.  There  shall  be  a  small 
reservoir  above  the  400°  mark.  The  thermometer 
shall  be  finished  at  the  top  with  a  small  glass  ring. 
The  stem  shall  be  made  of  enamel-backed  thermom- 
eter tubing,  but  not  of  Jena  16nl  glass.  The  bulb 
shall  be  made  of  Jena  16HI,  Corning  normal,  or  Jena 
or  Corning  borosilicate  glass. 

Every  fifth  graduation  shall  be  longer  than  the  in- 
termediate ones,  and  the  marks  shall  be  numbered  at 
every  interval  of  10°.  The  graduation  marks  shall  be 
clear-cut  and  fine,  and  the  numbering  clear-cut  and  dis- 
tinct. The  thermometer  shall  be  filled  above  the  mer- 
cury with  an  inert  gas  which  will  not  act  chemically 
or  contaminate  the  mercury.  The  pressure  of  the 
gas  shall  be  sufficient  to  prevent  separation  of  the 
mercury  column  at  all  temperatures  of  the  scale,  but 
the  upper  reservoir  shall  be  large  enough  so  that  the 
pressure  will  not  become  excessive  at  the  highest 
temperature. 

The  thermometer  shall  be  thoroughly  annealed  be- 
fore the  final  filling.  It  shall  be  pointed  for  use  at 
full  immersion. 

Each  thermometer  shall  be  provided  with  a  suitable 
case.  A  serial  number  for  identification  and  the 
word  "  Distillation  "  shall  be  engraved  on  the  stem. 


EXAMINATION   OF  PETROLEUM   THINNERS          23 

All  material  and  workmanship  shall  be  of  the  best 
grade. 

The  maximum  error  of  0°  to  200°  C.  shall  not  exceed 
0°.5  C.;  from  20Q°  to  300°  C.,  shall  not  exceed  1°  C.; 
and  from  300°  to  400°  C.,  shall  not  exceed  2°  C. 

The  thermometer  shall  conform  to  the  following 
dimensions: 

Total  length,  max.,  mm 385 

Diameter  of  stem,  mm 5.5-7.0 

Diameter  of  bulb,  mm 5. 5-7. 0 

Diameter  of  capillary,  min.,  mm 0. 1 

Length  of  bulb,  mm 11-15 

Distance,  0°  to  bottom  of  bulb,  mm 25-35 

Distance,  0°  to  400°  mark,  mm 280-300 

The  thermometer  shall  be  inserted  through  a  tight- 
fitting  cork  in  the  neck  of  the  flask,  so  that  the  top 
of  the  thermometer  bulb  will  be  on  a  level  with  the 
bottom  of  the  side  outlet  in  the  neck  of  the  flask  and 
in  the  center  of  the  neck. 

21.  Method  of  distillation.  The  flask,  connected 
with  the  condenser,  shall  be  filled  with  100  c.c.  of  the 
thinner  at  60°  F.,  which  shall  be  measured  in  the 
100-c.c.  receiving  cylinder.  The  same  cylinder  may 
be  used  without  drying  as  the  receiving  vessel  for  the 
distillate.  The  flask  shall  be  heated  directly  by  a 
suitable  burner. 

The  distillation  shall  proceed  at  the  rate  of  not 
less  than  4  or  more  than  5  c.c.  per  minute  into  the 
receiving  cylinder.  The  temperature  at  which  the 
first  drop  leaves  the  lower  end  of  the  condenser  shall 
be  considered  the  initial  boiling  point. 

Readings  of  the  quantity  in  the  receiver  shall  be 
taken  when  the  next  10°  point  is  reached,  and  for  every 
even  10°  thereafter.  For  example,  if  initial  boiling 
point  occurs  at  144°  C.,  then  the  first  reading  of  the 


24         PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

quantity  in  the  receiver  shall  be  made  at  150°  C., 
and  thereafter  at  160°,  170°,  etc. 

The  distillation  shall  be  continued  until  the  point 
is  reached  where  the  last  drop  is  vaporized,  when  a 
puff  of  white  vapor  usually  appears  in  the  bottom  of 
the  flask.  The  temperature  at  this  point  shall  be 
considered  the  end  or  dry  point  of  distillation. 

The  total  yield  of  distillate  shall  not  be  less  than 
97  per  cent. 

22.  Flash  point.  In  the  various  methods  now  in 
use  for  the  determination  of  the  flash  point  of  an  oil, 
the  temperature  at  which  it  flashes  is  not  a  definite 
factor  but  is  dependent  on  chemical  and  physical  con- 
ditions over  which  the  operator  has  no  control.  It  is 
an  indication  only  of  the  temperature  at  which  the 
oil  vapors  are  given  off  in  such  quantities  as  to  form 
an  inflammable  mixture  with  air,  and  is  not  necessarily 
a  factor  influencing  the  value  of  an  oil  for  a  particular 
purpose.  In  the  paint  and  varnish  industries,  however, 
it  is  an  important  factor,  inasmuch  as  thinners  of  too 
low  a  flash  point  are  undesirable  on  account  of  fire  risk. 

Factors  to  be  considered  in  making  the  determina- 
tion: In  taking  the  flash  point,  a  fresh  sample  should 
always  be  used.  The  conditions  of  the  test  should  be 
as  near  to  those  found  in  practice  as  is  possible.  The 
oil  should  not  be  allowed  to  stand  in  the  cup  too  long 
before  the  flash  point  is  taken,  as  the  lighter  portions 
of  the  volatile  oils  will  be  given  off,  thus  raising  the 
flash  point.  Barometric  pressure  influences  the  flash 
point  to  a  large  degree.  A  rise  of  1  mm.  in  the  baro- 
metric pressure  changes  the  flash  point  on  an  average 
of  0.0381°  C.  The  barometric  pressure  should  be 
taken  at  the  same  time  as  flash  points  are  made,  and 
the  correction  made. 


EXAMINATION  OF  PETROLEUM   THINNERS          25 

23.  Shape.     The  shape  and  size  of  the  cup  are  im- 
portant.    The   greater   the   area   exposed,   the   more 
rapid  will  be  the  evolution  of  the  lighter  vapors  and 
the  easier  it  will  be  to  obtain  an  inflammable  mixture, 
thus  lowering  the  flash  point.     The  cup  should  al- 
ways be  filled  to  the  mark  with  cold  oil  and  the  warm- 
ing applied  very  cautiously.     The  expansion  of  the 
oil  above  the  mark  due  to  the  warming  is  generally 
disregarded.     The  rate  of  heating  should  be  such  as 
to  keep  equilibrium  between  the  liquid  and  gaseous 
phases  with  the  temperature  rising  not  over  3°  C.  per 
minute.    The  heating   should  begin   at  least   10°  C. 
below  the  flash  point  in  order  that  the  proper  equi- 
librium may  be  reached  at  the  point  where  the  oil 
flashes.    This  must  be  determined  by  a  preliminary 
test, 

24.  Stirring.     It  is  necessary  to  stir  the  oil  when 
making  a  flash  point  determination,  as  the  tempera- 
ture of  the  oil  in  different  parts  of  the  cup  may  vary 
from  3°-5°  C.  or  even  more. 

25.  Flame.    A  test  flame,  the  size  of  the  ivory  bead 
on  the  cover  of  the  Abel-Pensky  tester,  burns  about 
0.1  cu.  ft.  of  coal  gas  per  hour.    A  test  flame  of  half 
this  size  raises  the  flash  point  1°  and  a  flame  one 
and  a  half  times  the  size  of  the  bead  lowers  the  flash 
point  0.5°. 

It  is  important  that  the  test  flame  be  kept  a  con- 
stant distance  from  the  surface  of  the  oil.  If  the 
flame  is  too  near  the  oil,  local  heating  will  result,  thus 
causing  the  flash  point  to  be  lowered.  Conversely, 
if  the  flame  is  too  far  away  from  the  oil,  it  will  take 
longer  for  the  vapors  to  be  given  off  in  sufficient  quan- 
tities to  flash  and  the  flash  point  will  be  higher. 
A  coal  gas  flame  gives  a  flash  point  0.3°  lower  than 


26         PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

does  an  oil  test  flame.  The  electric  spark  gives  a 
variable  but  usually  a  lower  result.  On  account  of 
the  variable  intensity  and  duration,  the  results  are 
bound  to  be  uncertain  and  should  not  be  used,  there- 
fore, with  an  official  instrument.  The  duration  of 
the  exposure  of  the  test  flame  to  the  oil  vapors  is 
important,  chiefly,  on  account  of  local  heating. 

26.  The  Abel-Pensky  tester  and    U.  S.  Bureau   of 
Mines  Flash  Tester.     The  tester  most  widely  used 
and  which   satisfactorily  meets   the  required   condi- 
tions is  the  closed  Abel-Pensky  tester,  with  stirrer, 
overflow    cup,    water   or   oil   bath    and    mechanical 
exposure  of  the  test  flame  for  exactly  one  second,  and 
fitted    with    standardized    thermometers.     It    is    the 
official  instrument  in  Austria-Hungary,  Belgium,  Den- 
mark,   France,    Germany,    Great    Britain,    Holland, 
Italy,  Japan,  Norway,  Roumania,  Russia,  and  Sweden. 

The  U.  S.  Bureau  of  Mines  Flash  Tester  was  de- 
signed by  the  Bureau  of  Mines  after  having  made 
an  exhaustive  study  of  the  subject  from  previously 
obtained  data  and  actual  tests.  It  has  the  following 
advantages  over  other  types:  It  most  nearly  repro- 
duces the  actual  working  conditions  under  which 
oils  are  used;  it  is  entirely  mechanical  in  operation, 
thereby  eliminating  the  personal  error  in  the  making 
of  the  test;  it  gives  results  that  are  reproduceable  by 
another  operator  and  are  directly  comparable  with 
those  of  the  standard  instruments  used  by  all  the 
leading  European  and  Asiatic  countries. 

27.  War    Department    specifications    for    mineral 
spirits.     This  shall  be  a  hydrocarbon  distillate,  water 
white,  neutral,  clear  and  free  from  water.     It  shall 
have  no  darkening  effect  when  mixed  with  basic  car- 
bonate white  lead. 


EXAMINATION   OF  PETROLEUM   THINNERS          27 

When  10  c.c.  are  put  in  a  glass  crystallizing  dish 
2|  inches  in  diameter,  and  placed  on  a  steam  bath 
for  2^  hours,  the  residue  must  not  exceed  .03  gms. 

When  tested  according  to  the  standard  tests  for 
paint  thinners  other  than  turpentine,  prescribed  by 
the  American  Society  for  Testing  Materials,  the  flash 
point  shall  not  be  less  than  29°  C.  (85°  F.)  in  a  closed 
tester,  and  in  the  distillation  test  the  first  drop  must 
issue  from  the  condenser  at  a  temperature  not  below 
129°  C.  (265°  F.),  and  97  per  cent  must  distill  below 
243°  C.  (470°  F.).  Adopted  May  7,  1918, 


CHAPTER  III 

EXAMINATION  OF  TURPENTINE 

28.  Classification    of    turpentine.     Turpentine    dis- 
tilled from  the  oleoresin  of  the  pine  is  known  to  the 
trade   as    gum   turpentine   or    spirits    of   turpentine, 
while  turpentine  obtained  from  resinous  wood  is  known 
as  wood  turpentine.     Wood  turpentine  may  be  ex- 
tracted with  volatile  solvents,  by  steam  or  by  destruc- 
tive distillation.     Manufacturers  of  wood  turpentine 
now  produce  a  product  that  comes  within  the  accepted 
physical  and  chemical  limits  of  gum  turpentine.     The 
specifications  should,  therefore,  be  the  same  for  both. 
The  purchaser   should,   however,   state  whether  the 
gum  or  the  wood  turpentine  is  desired. 

29.  Specifications.     The  following  specifications  and 
methods  of  analysis,  except  for  the  flash  point  and 
odor,  are  those  proposed  by  the  American  Society  for 
Testing  Materials.1 

30.  General    appearance.     The    turpentine    should 
be  clear  and  free  from  suspended  matter  and  water. 

31.  Odor.     Gum  turpentine  should  have  a  sweet, 
pleasing  odor  and  not  a  woody  smell.     Wood  tur- 
pentine should  not  have  a  pungent,  smoky  or  offen- 
sive creosote  odor.     In  fact,  the  odor  should  not  be 
any  stronger  or  more  penetrating  than  that  of  gum 
spirits,  though  it  may  be  quite  different  in  character. 

1  Proceedings  of  the  American  Society  for  Testing  Materials,  Vol.  XIV, 
Part  1,  page  342,  and  Vol.  XV,  1915,  Part  1,  page  265. 
28 


EXAMINATION   OF  TURPENTINE  29 

32.  Color.     The  color  shall  be  "  Standard  "  when  a 
layer  50  mm.  in  depth  is  as  light  or  lighter  than  a 
No.  1  Yellow  Lovibond  glass. 

33.  Flash  point.     If  it  is  necessary  to  determine 
the  flash  point,  the  determination  may  be  made  as 
described  in  the  preceding  chapter. 

34.  Specific   gravity.     The   specific   gravity   should 
not  be  less  than  0.862  or  more  than  0.872  at  15.5°  C. 

The  determination  may  be  made  at  room  tempera- 
ture, using  the  Tagliabue  hydrometer  for  turpentine, 
graduated  in  .001  divisions,  having  a  range  from  0.830 
to  0.890.  The  temperature  of  the  turpentine  should 
be  carefully  taken  and  corrected  to  15.5°  C.  by  means 
of  Table  III,  or  by  using  the  coefficient  of  thermal 
expansion  factor,  0.00082,  for  each  degree  Centigrade 
that  the  temperature  at  which  the  determination  was 
made  differs  from  15°  C. 

35.  Refractive   index.     The  refractive  index   shall 
not  be  less  than  1.468  or  more  than  1.478  at  15.5°  C. 
The  determination  is  made  at  any  convenient  tempera- 
ture with  an  accurate  instrument  and  the  results  cal- 
culated to  15.5°  C.,  using  the  factor  .00045  tor  each 
degree  that  the  temperature  of  determination  differs 
from  15.5°  C. 

36.  Distillation.     The  initial  boiling  point  shall  not 
be  less  than  150°  C.  and  not  more  than  160°  C.     Ninety 
per  cent  of  the  turpentine  shall  distill  below  170°  C. 

The  distillation  should  be  made  with  an  Engler 
flask  and  condenser.  The  heating  is  done  by  placing 
the  flask  in  a  glycerine  or  oil  bath  of  the  general  type 
described  in  bulletin  No.  135  of  the  Bureau  of  Chemis- 
try, Department  of  Agriculture.  Fit  the  flask  with  a 
thermometer,  reading  from  145*  C.  to  200°  C.,  in  such 
a  way  that  the  mercury  bulb  will  be  opposite  the 


30         PAINT  VEHICLES,  JAPANS  AND  VARNISHES 


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EXAMINATION  OF  TURPENTINE  31 

side  arm  and  the  175°  mark  below  the  cork.  Place 
100  c.c.  of  the  turpentine  to  be  examined  in  the  flask, 
connect  with  the  condenser,  insert  the  stopper  bear- 
ing the  thermometer  and  heat  until  the  distillation 
begins.  Conduct  the  distillation  so  that  the  distillate 
passes  over  at  the  rate  of  two  drops  per  second.  Note 
the  initial  distilling  temperature  and  the  percentage 
distilling  below  170°  C. 

38.  Polymerization.     The     polymerization     residue 
shall  not  exceed  2  per  cent,  and  its  refractive  index 
shall  not  be  less  than  1.500  at  15.5°  C. 

Place  20  c.c.  of  exactly  38  times  normal  (100.92  per 
cent)  sulphuric  *  acid  in  a  graduated  narrow-neck 
stoppered  Babcock  flask,  and  place  in  ice  water  and 
cool.  Add  slowly  5  c.c.  of  the  turpentine  to  be  tested. 
Gradually  mix  the  contents,  cooling  from  time  to  time 
and  not  allowing  the  temperature  to  rise  above  60°  C. 
When  the  mixture  no  longer  warms  up  on  mixing, 
agitate  and  heat  on  a  water  bath  at  from  60°  to 
65°  C.  for  ten  minutes,  keeping  the  contents  well  mixed 
by  shaking  five  or  six  times  during  the  heating.  Do 
not  stopper  after  the  turpentine  has  been  added,  as 
it  may  explode.  Cool  to  room  temperature  and  add 
concentrated  sulphuric  acid  till  the  unpolymerized 
portion  rises  into  the  graduated  neck.  Centrifuge  at 
about  1200  revolutions  per  minute  from  four  to  five 
minutes,  or  allow  the  flask  and  contents  to  stand  12 
hours.  Read  the  unpolymerized  portion,  notice  its 
consistency  and  color  and  determine  its  refractive 
index. 

39.  Pine  oil  and  heavy  turpentine.     The  large  in- 
crease in  the  use  of  petroleum  thinners,  in  the  paint 
and  varnish  industry,  has  resulted  in  a  corresponding 
decrease  in  the  demand  for  turpentine  and  has  like- 


32         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

wise  restricted  the  consumption  of  the  heavy  refined 
distillates,  known  to  the  trade  as  pine  oil.  On  ac- 
count of  this  limited  demand  these  products  have 
not  become  definitely  standardized,  and  unless  the 
constants,  especially  the  specific  gravity  and  the  dis- 
tillation figures,  are  specified,  the  purchaser  may  re- 
ceive, under  the  name  of  pine  oil,  distillates  varying 
in  gravity  from  0.880  to  0.940  with  corresponding 
variations  in  distillation  figures  and  working  proper- 
ties of  the  paint,  enamel,  or  varnish  in  which  the  pine 
oil  is  used.  Table  IV  gives  the  distillation  figures  of 
four  different  samples  of  pine  oil  submitted  to  the 
author  for  examination  within  one  month.  This 
table  clearly  indicates  the  lack  of  standardization  re- 
ferred to  above.  The  advantages  to  be  derived  from 
the  use  of  pine  oil  are  discussed  at  length  by  Toch.1 

40.  Requirements.     A  pine  oil,   to  be  acceptable, 
should  have  a  pleasant,  aromatic  odor,  suggestive  of 
camphor  or  juniper  seed,  and  a  coefficient  of  evapo- 
ration suited  to  the  requirements  of  the  paint,  enamel 
or  varnish  in  question.     An  insufficiently  refined  oil 
will  cause  serious  complaint,  when  used  in  finishes  for 
interior  work,  on  account  of  the  obnoxious  odor,  dur- 
ing the  drying,  due  to  the  empyreumatic  compounds 
present. 

41.  Presence   of   water.     The   pine   oils   examined 
by  the  author  have  been  found  to  contain  2-5  per 
cent  of  water,  which  for  certain  purposes  is  beneficial 
and,  except  when  used  in  nitro-cellulose  lacquers,  has 
not  been  found  to  be  detrimental.     The  degree  of 
cloudiness  manifested  when  two  parts  of  pine  oil  are 
mixed  with  one  part  of  naphtha  is  indicative  of  the 
amount  of  water  present. 

1  Jour.  Ind.  Eng.  Chem.,  Vol.  VI,  page  720. 


EXAMINATION   OF  TURPENTINE 


33 


TABLE  IV 
42.  Distillation  of  pine  oils  by  the  author 


Temp 

100°  t 
150 
170 
180 
190 
200 
210 
220 
230 
240 
250 
R< 

erature 
0  150°  C 

I 

Per  cent 
2.0 
3.0 
22.0 
26.0 
20.0 
18.0 
8.0 
1.0 

170  
180  
190 

200  
210  

220 

230 

240  
'  250  
'  260  
;sidue  

II 

Per  cent 


III 

Per  cent 

2.0 


100.0 


5.0 
14.0 
51.5 
15.5 

5.5 

4.0 

2.0 

2.5       

100.0          100.0 


7.0 
1.5 
1.5 
1.5 
2.0, 
2.0 
2.0 
80.5 


43.  Examination  in  paint  products.  Owing  to  the 
high  boiling  fractions  present  in  pine  oil,  it  can  be 
removed  for  estimation  from  a  paint  or  enamel  only 
with  much  difficulty,  requiring  at  least  two  hours 
treatment  with  steam  as  described  in  Chapter  XIII. 
The  specific  gravity  of  the  distillate  should  be  noted 
and  the  rate  of  evaporation  determined  by  superim- 
posing 3  drops  of  the  oil  on  a  sheet  of  dry  paper. 
Polymerization  with  sulphuric  acid  does  not  yield 
satisfactory  results. 


44.  Analysis  of  pine  oils  l 

Color 

I 

Faintly 
Yellow 

Sp.  Gr.  15.  5°  C.... 
Acid  value  
Iodine  value  
Flash  point  °  F.  . 
Per    cent    loss    on 
steam  bath  after 
9  hrs  

0.9423 
0.68 
142.5 
170° 

93.4 

TABLE  V 


n 

Nearly 
Water 
White 

0.9427 
0.29 
118.4 

175° 


96.3 


Water 
White 

0.9338 

0.51 
125 .4 
145° 


97.3 


IV 

Straw 
Color 

0.9330 

0.59 
161.5 
160° 


V 

Amber 
Pale 

0.  9291 
0.49 
173.9 

148° 


85.7 


J.  Md.  &  Chem.  Eng.  Chem.,  Vol.  VI,  No.  9,  page  722. 


34         PAINT  VEHICLES    JAPANS  AND  VARNISHES 

TABLE  V 
45.  Analysis  of  pine  oils  (Continued) 


VI 

VII 

vni           IX 

Color 

Straw 

Water 

Straw           Water 

Color 

White 

Color            White 

Sp.  gr.  15.5°  C  
Acid  value  

0.9355      0.9382 
0.70          0.17 

0.9350      0.9383 
0.73          0.27 

Iodine  value 

143.2 

129.8 

142.7        124.4 

Flash  point  °  F  

168° 

175° 

160°           176° 

Per  cent  loss  on  steam 

bath 

after  9  hrs 

92.7 

98.6 

95.1          98.7 

TABLE 

VI 

46.  Fractional  distillation  of  commercial  pine  oil  l 

Temperature 

Fraction  in 

Total  Distil-     <,      r     ,  .  ,.<,  r 
late            bp>  -  r<      -5   C> 

per  cent 

per  cent 

of  fractions 

Water  100°  

2 

2 

174°-194° 

5 

7 

0.882 

194°-205°...  :.... 

11 

18 

0.920 

205°-208° 

10 

28 

0.933 

208°-210° 

25 

53 

0.939 

210°-213°  

35 

88 

0.941 

213°-216°  

6 

94 

0.942 

216°-218°  

1 

95 

0.942 

218MXX).  .  . 

4 

99 

Ibid.,  page  723. 


CHAPTER  IV 

ALCOHOLS  AND  ACETONES 

47.  Wood  alcohol,   characteristics.     Wood  alcohol, 
to  be  acceptable  for  the  manufacture  of  paint  and 
varnish  removers,  shellac,  stains,  etc.,  should  contain 
at  least  97  per  cent  alcohol  and  should  not  have  a 
raw  pungent  odor.     For  use  in  the  manufacture  of 
nitro-cellulose  lacquers,  99  per  cent  alcohol  should  be 
used. 

48.  Impurities.    Acetone,   the  heavy  ketones  and 
methyl  acetate  may  be  present  in  an  insufficiently 
refined  alcohol.     These  impurities  may  be  estimated 
as  described  in  this  chapter. 

49.  Specific  gravity.    Where  only  a  close  approxi- 
mation of  results  is  required,  the  gravity  or  proof  can 
be  obtained  by  following  the  procedure  and  tables  for 
denatured  alcohol.    Accurate  results  may  be  obtained 
by  determining  the  specific  gravity  with  a  picnometer 
at  15.5°  C.  and  using  the  following  table,  No.  VII. 

50.  The    uses    of    denatured    alcohol.     Denatured 
alcohol  is  used  in  the  manufacture  of  shellac  and 
other  spirit  varnishes,  in  stains,  graining  compounds, 
and  occasionally  in  emulsions  for  mixed  paints  to  pre- 
vent freezing. 

51.  Composition.     Unless   otherwise   provided   for, 
alcohol  is  completely  denatured  under  either  of  the 
following  formulas: 

1.  To  every  100  parts  by  volume  of  ethyl  alcohol 
of  the  desired  proof  (not  less  than  180°)  there  shall 
be  added  100  parts  by  volume  of  approved  benzine. 

35 


36         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

TABLE  VII 

62.  Specific   gravity   at  j|s  c-  of   mixtures  (by  volume)    of   methyl 
alcohol  and  water1 


?: 

M 

d 

fc 

u 

£ 

5g 

£ 

I 

Per  Ceni 
Alcohol 
ume  at  1 

Q 

Si 

«i 

Q 

si 
h£ 

IS 
*§ 

Per  Cen 
Weight 

3* 
ll 

0 

1.00000 

50 

0.93326 

0 

0.000 

50 

57.712 

1 

.99851 

51 

.93155 

1 

1.253 

51 

58.739 

2 

.99703 

52 

.  92982 

2 

2.502 

52 

59.759 

3 

.  99560 

53 

.92806 

3 

3.746 

53 

60.773 

4 

.99422 

54 

.92626 

4 

4.986 

54 

61.781 

5 

.99283 

55 

.92443 

5 

6.222 

55 

62.783 

6 

.99146 

56 

.92256 

6 

7.454 

56 

63.778 

7 

.99011 

57 

.92067 

7 

8.682 

57 

64.767 

8 

.98877 

58 

.  91877 

8 

9.907 

58 

65.750 

9 

.  98746 

59 

.91682 

9 

11.128 

59 

66.725 

10 

.  98621 

60 

.91483 

10 

12.345 

60 

67.693 

11 

.  98496 

61 

.91282 

11 

13.559 

61 

68.654 

12 

.98370 

62 

.  91079 

12 

14.770 

62 

69.607 

13 

.  98247 

63 

.  90873 

13 

15.977 

63 

70.552 

14 

.  98125 

64 

.90663 

14 

17.181 

63 

71.490 

15 

.98003 

65 

.90450 

15 

18.382 

65 

72.420 

16 

.97884 

66 

.90234 

16 

19.579 

66 

73.344 

17 

.97766 

67 

.90014 

17 

20.773 

67 

74.262 

18 

.97648 

68 

.  89790 

18 

21.963 

68 

75.172 

19 

.  97530 

69 

.89561 

19 

23.149 

69 

76.077 

20 

.97413 

70 

.  89327 

20 

24.332 

70 

76.976 

21 

.  97295 

71 

.  89088 

21 

25.512 

71 

77.864 

22 

.97177 

72 

.88844 

22 

26.688 

72 

78.746 

23 

.97058 

73 

.88596 

23 

27.860 

73 

79.618 

24 

.  96936 

74 

.88346 

24 

29.029 

74 

80.  480 

25 

.96820 

75 

.88092 

25 

30.  193 

'  75 

81.336 

26 

.96700 

76 

.87836 

26 

31.354 

76 

82.  182 

27 

.  96580 

77 

.87578 

27 

32.510 

77 

83.022 

28 

.96459 

78 

.87312 

28 

33.662 

78 

83.855 

29 

.96338 

79 

.87040 

29 

34.809 

79 

84.680 

30 

.96216 

80 

.86760 

30 

35.952 

80 

85.499 

31 

.96091 

81 

.86474 

31 

37.091 

81 

86.310 

32 

.  95966 

82 

.86180 

32 

38.224 

82 

87.110 

33 

.  95838 

83 

.85883 

33 

39.352 

83 

87.899 

34 

.  95708 

84 

.85582 

34 

40.476 

84 

88.677 

1  Circular  No.  19  of  the  Bureau  of  Standards,  pages  23-24. 


ALCOHOLS  AND  ACETONES 
TABLE  VII     (Continued) 


37 


H. 

ii. 

j. 

4 

so 

d 

*|     O 

d 

^ 

>>d 

>> 

^Q 

•^k 

&  \8> 

joo 

£1.3 

•H 

£1 

-O  o^ 

i|5 

Q 

Sii 

rl|-H 
Q 

Si 

n 

Si 

$i 

ill 

Hi 

!£ 

ti 

ll 

y 

35 

.  95576 

85 

.  85276 

35 

41.594 

85 

89.448 

36 

.95443 

86 

.84967 

36 

42.708 

86 

90.212 

37 

.  95308 

87 

.84646 

37 

43.816 

87 

90.968 

38 

.  95170 

88 

.  84314 

38 

44.919 

88 

91.716 

39 

.  95029 

89 

.83971 

39 

46.016 

89 

92.456 

40 

.  94886 

90 

.83623 

40 

47.109 

90 

93.188 

41 

.  94741 

91 

.83269 

41 

48.  195 

91 

93.912 

42 

.  94593 

92 

.  82907 

42 

49.277 

92 

94.627 

43 

.  94443 

93 

.  82538 

43 

50.353 

93 

95.326 

44 

.  94291 

94 

.  82163 

44 

51.422 

94 

96.017 

45 

.  94136 

95 

.81772 

45 

52.486 

95 

96.697 

46 

.93979 

96 

.  81363 

46 

53.544 

96 

97.370 

47 

.  93820 

97 

.80942 

47 

54.595 

97 

98.039 

48 

.93657 

98 

.80514 

48 

55.639 

98 

98.696 

49 

.93493 

99 

.80082 

49 

56.678 

99 

99.351 

50 

.93326 

100 

.79647 

50 

57.712 

100 

100.000 

2.  To  every  100  parts  by  volume  of  ethyl  alcohol 
of  the  desired  proof  (not  less  than  180°)  there  shall 
be  added  2  parts  by  volume  of  approved  wood  alcohol 
and  one-half  part  by  volume  of  approved  pyridin 
bases. 

The  Commissioner  of  Internal  Revenue  has  au- 
thorized the  use  of  one  specially  denatured  alcohol  for 
the  manufacture  of  shellac  varnishes,  wood  finishes 
and  varnish  removers.  The  denaturing  hi  this  case 
is  accomplished  by  adding  5  gallons  of  approved  wood 
alcohol  to  100  gallons  ethyl  alcohol. 

53.  Proof  spirit.1  Proof  spirit  is  held  and  taken  to 
be  that  alcoholic  liquor  which  contains  one-half  its 
volume  of  alcohol  of  a  specific  gravity  of  seven  thou- 

1  Gangers'  Manual,  U.  S.  Internal  Revenue,  page  413. 


38         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

sand  nine  hundred  and  thirty-nine  ten-thousandths 
(0.7939),  at  60°  Fahrenheit,  referred  to  water  at  60° 
Fahrenheit  as  unity.  Proof  spirit  has  at  60°  Fah- 
renheit a  specific  gravity  of  0.93426,  100  parts  by 
volume  of  the  same  consisting  of  50  parts  of  abso- 
lute alcohol  and  53.71  parts  of  water.  The  difference 
of  the  sum  of  the  parts  of  alcohol  and  water  and  the 
resulting  100  parts  of  proof  spirit  is  due  to  the  con- 
traction which  takes  place  when  alcohol  and  water 
combine. 

54.  Correction  for  temperature.     It  is  seldom,  how- 
ever, that  the  alcohol  is  inspected  at  60°  F. ;    and  as 
its  density  varies  with  the  temperature,  a  correction 
is  necessary  for  a  temperature  differing  from  60°,  the 
hydrometer  giving  too  low  an  indication  for  tempera- 
tures below  60°  and  too  high  for  those  above.     This 
correction,  applied  to  the  indication  of  the  hydrom- 
eter, gives  the  true  per  cent,  or  what  the  reading  of 
the  hydrometer  would  be  were  the  alcohol  at  60°. 

55.  Hydrometer  to  be  used.     In  1913  a  new  style 
of  hydrometer  was  prescribed  for  use  by  the  Internal 
Revenue    Department.     For    ordinary   use   a   No.   7 
stem  (157°  to  181°  proof)  and  a  No.   8  stem   (177° 
to  200°  proof)  are  sufficient. 

56.  Determination.     The  sample  is  poured  into  a 
cylinder,  sufficient  space  being  left  for  the  displace- 
ment of  the  liquid  when  the  stem  is  inserted,  and  the 
hydrometer  carefully  placed  therein.     The  eye  should 
be  held  slightly  below  the  level  of  the  liquid,  and  the 
highest  immersed  reading  on  the  stem  is  taken  as  the 
apparent    indication.     The    thermometer    should    be 
placed  in  the  liquid  and  read  immediately  after  the 
reading  of  the  proof  indication.     The  true  proof  will 
be  determined  by  reference  to  the  following  table. 


ALCOHOLS  AND  ACETONES 


39 


The  left-hand  column,  headed  ''Indication,"  contains 
the  reading  of  the  hydrometer,  and  on  the  same  hori- 
zontal line,  in  the  body  of  the  table,  in  the  "  Tempera- 
ture "  column  indicated  by  the  thermometer,  is  found 
the  corrected  reading  or  true  per  cent  of  proof  which, 
divided  by  2,  gives  the  percentage  of  alcohol  present. 

TABLE  VIII 
67.  True  per  cent  of  proof  for  temperatures  between  51°  F.  and  60°  F. 


Indica- 
tion. 

51°  F. 

52°  F. 

53°  F. 

54°  F. 

55°  F. 

56°  F. 

57°  F. 

68°  F. 

59°  F. 

60°  F. 

161 

163.9 

163.6 

163.2 

162.9 

162.6 

162.3 

162.0 

161.6 

161.3 

161.0 

162 

164.9 

164.6 

164.2 

163.9 

163.6 

163.3 

163.0 

162.6 

162.3 

162  0 

163 

165.9 

165.6 

165.2 

164.9 

164.6 

164.3 

164.0 

163.6 

163.3 

163.0 

164 

166.9 

166.6 

166.2 

165.9 

165.6 

165.3 

165.0 

164.6 

164.3 

164.0 

165 

167.9 

167.6 

167.2 

166.9 

166.6 

166.3 

166.0 

165.6 

165.3 

165.0 

166 

168.9 

168.6 

168.2 

167.9 

167.6 

167.3 

167.0 

166.6 

166.3 

166.0 

167 

169.8 

169.5 

169.2 

168.9 

168.6 

168.3 

168.0 

167.6 

167.3 

167.0 

168 

170.8 

170.5 

170.2 

169.9 

169.6 

189.3 

169.0 

168.6 

168.3 

168  0 

169 

171.8 

171.5 

171.2 

170.9 

170.6 

170.3 

170.0 

169.6 

169.3 

169.0 

170 

172.8 

172.5 

172.2 

171.9 

171.6 

171.3 

171.0 

170.6 

170.3 

170.0 

171 

173.8 

173.5 

173.2 

172.9 

172.6 

172.3 

172.0 

171.6 

171.3 

171.0 

172 

174.7 

174.4 

174. 

173.8 

173.5 

173.2 

172.9 

172.6 

172.3 

172.0 

173 

175.6 

175.3 

175. 

174.8 

174.5 

174.2 

173.9 

173.6 

173.3 

173.0 

174 

176.6 

176.3 

176. 

175.8 

175.5 

175.2 

174.9 

174.6 

174.3 

174  0 

175 

177.6 

177.3 

177.1 

176.8 

176.5 

176.2 

175.9 

175.6 

175.3 

175.0 

176 

178.6 

178.3 

178. 

177.8 

177.5 

177.2 

176.9 

176.6 

176.3 

176.0 

177 

179.6 

179.3 

179.1 

178.8 

178.5 

178.2 

177.9 

177.6 

177.3 

177.0 

178 

180.5 

180.2 

180.0 

179.7 

179.4 

179.1 

178.8 

178.6 

178.3 

178.0 

179 

181. 

181.2 

180.9 

180.7 

180.4 

180.1 

179.8 

179.6 

179.3 

179.0 

180 

182. 

182.2 

181.9 

181.7 

181.4 

181.1 

180.8 

180.6 

180.3 

180.0 

181 

183. 

183.2 

182.9 

182.7 

182.4 

182.1 

181.8 

181.6 

181.3 

181.0 

182 

184. 

184.2 

183.9 

183.7 

183.4 

183.1 

182.8 

182.6 

182.3 

182.0 

183 

185. 

185.2 

184.9 

184.7 

184.4 

184.1 

183.8 

183.6 

183.3 

183.0 

184 

186.3 

186.1 

185.8 

185.6 

185.3 

185.0 

184.8 

184.5 

184.3 

184.0 

185 

187.3 

187.1 

186.8 

186.6 

186.3 

186.0 

185.8 

185.5 

185.3 

185.0 

186 

188.3 

188.0 

187.8 

187.5 

187.3 

187.0 

186.8 

186.5 

186.3 

186.0 

187 

189.2 

189.0 

188.7 

188.5 

188.3 

188.0 

187.8 

187.5 

187.3 

187.0 

188 

190.2 

190.0 

189.7 

189. 

189.3 

189.0 

188.8 

188.5 

188.3 

188.0 

189 

191.1 

190.9 

190.6 

190. 

190.2 

190.0 

189.7 

189.5 

189.2 

189.0 

190 

192.1 

191.9 

191.6 

191. 

191.2 

191.0 

190.7 

190.5 

190.2 

190.0 

191 

193.1 

192.9 

192.6 

192. 

192.2 

192.0 

191.7 

191.5 

191.2 

191.0 

192 

194.0 

193.8 

193.6 

193. 

193.2 

193.0 

192.7 

192.5 

192.2 

192.0 

193 

195.0 

194.8 

194.6 

194. 

194.2 

194.0 

193.7 

193.5 

193.2 

193.0 

194 

196.0 

195.8 

195.6 

195. 

195.2 

195.0 

194.7 

194.5 

194.2 

194.0 

195 

196.9 

196.7 

196.5 

196.3 

196.1 

195.9 

195.7 

195.4 

195.2 

195.0 

196 

197.9 

197.7 

197.5 

197.3 

197.1 

196.9 

196.7 

196.4 

196.2 

196.0 

197 

198.8 

198.7 

198.5 

198.3 

198.1 

197.9 

197.7 

197.4 

197.2 

197.0 

198 

199.9 

199.7 

199.5 

199.3 

199.1 

198.9 

198.7 

198.4 

198.2 

198.0 

199 

200.0 

199.8 

199.6 

199.4 

199.2 

199.0 

200  0 

40         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 


True  per  cent  of  proof  for  temperatures  between  61°  F.  and  70°  F. 


Indica- 
tion. 

61°F. 

62°  F. 

63°  F. 

64°  F. 

65°  F. 

66°  F. 

67°  F. 

68°  F. 

69°  F. 

70°  F. 

161 

160.7 

160.3 

160.0 

159.6 

159.3 

159.0 

158.7 

158.3 

158.0 

157.7 

162 

161.7 

161.3 

161.0 

160.6 

160.3 

160.0 

159.7 

159.3 

159.0 

158.7 

163 

162.7 

162.4 

162.0 

161.7 

161.4 

161. 

160.7 

160.4 

160.0 

159.7 

164 

163.7 

163.4 

163.0 

162.7 

162.4 

162. 

161.7 

161.4 

161.0 

160.7 

165 

164.7 

164.4 

164.0 

163.7 

163.4 

163. 

162.7 

162.4 

162.0 

161.7 

166 

165.7 

165.4 

165.0 

164.7 

164.4 

164. 

163.7 

163.4 

163.0 

162.7 

167 

166.7 

166.4 

166.0 

165.7 

165.4 

165. 

164.8 

164.4 

164.1 

163.8 

168 

167.7 

167.4 

167.0 

166.7 

166.4 

166. 

165.8 

165.4 

165.1 

164.8 

169 

168.7 

168.4 

168.0 

167.7 

167.4 

167. 

166.8 

166.4 

166.1 

165.8 

170 

169.7 

169.4 

169.0 

168.7 

168.4 

168. 

167.8 

167.4 

167.1 

166.8 

171 

170.7 

170.4 

170.0 

169.7 

169.4 

169. 

168.8 

168.4 

168.1 

167.8 

172 

171.7 

171.4 

171.0 

170.7 

170.4 

170. 

169.8 

169.5 

169.2 

168.9 

178 

172.7 

172.4 

172. 

171.8 

171.5 

171.2 

170.9 

170.5 

170.2 

169.9 

174 

173.7 

173.4 

173. 

172.8 

172.5 

172.2 

171.9 

171.5 

171.2 

170.9 

175 

174.7 

174.4 

174. 

173.8 

173.5 

173.2 

172.9 

172.6 

172.3 

172.0 

176 

175.7 

175.4 

175. 

174.8 

74.5 

174.2 

173.9 

173.6 

173.3 

173.0 

177 

176.7 

176.4 

176. 

175.8 

75.5 

175.2 

174.9 

174.7 

174.4 

174.1 

178 

177.7 

177.4 

177. 

176.8 

76.5 

176.2 

175.9 

175.7 

175.4 

175.1 

179 

178.7 

178.4 

178. 

177.8 

77.5 

177.2 

176.9 

176.7 

176.4 

176.1 

180 

179.7 

179.4 

179.2 

178.9 

78.6 

178.3 

178.0 

177.7 

177.4 

177.1 

181 

180.7 

180.4 

180.2 

179.9 

179.6 

179.3 

179.0 

178.8 

178.5 

178.2 

182 

181.7 

181.4 

181.2 

180'.  9 

180.6 

180.3 

180.0 

179.8 

179.5 

179.2 

183 

182.7 

182.4 

182.2 

181.9 

181.6 

181.3 

181.0 

180.8 

180.5 

180.2 

184 

183.7 

183.4 

183.2 

182.9 

182.6 

182.3 

182.0 

181.8 

181.5 

181.2 

185 

184.7 

184.4 

184.2 

183.9 

183.6 

183.3 

183.1 

182.8 

182.6 

182.3 

186 

185.7 

185.5 

185.2 

185.0 

184.7 

184.4 

184.1 

183.9 

183.6 

183.3 

187 

186.7 

186.5 

186.2 

186.0 

185.7 

185.4 

185.1 

184.9 

184.6 

184.3 

188 

187.8 

187.5 

187.3 

187.0 

186.8 

186.5 

186.2 

186.0 

185.7 

185.4 

189 

188.8 

188.5 

188.3 

188.0 

187.8 

187.5 

187.3 

187.0 

186.8 

186.5 

190 

189.8 

189.5 

189.3 

189.0 

188.8 

188.6 

188.3 

188.1 

187.8 

187.6 

191 

190.8 

190.5 

190.3 

190.0 

189.8 

189.6 

189.3 

189.1 

188.8 

188.6 

192 

191.8 

191.6 

191.3 

191.1 

190.9 

190.7 

190.4 

190.2 

189.9 

189.7 

193 

192.8 

192.6 

192.3 

192.1 

191.9 

191.7 

191.4 

191.2 

190.9 

190.7 

194 

193.8 

193.6 

193.3 

193.1 

192.9 

192.7 

192.4 

102.2 

191.9 

191.7 

195 

194.8 

194.6 

194.3 

194.1 

193.9 

193.7 

193.5 

193.2 

193.0 

192.8 

196 

195.8 

195.6 

195.3 

195.1 

194.9 

194.7 

194.5 

194.2 

194.0 

193.8 

197 

196.8 

196.6 

196.4 

196.2 

196.0 

195.8 

195.5 

195.3 

195.0 

194.8 

198 

197.8 

197.6 

197.4 

197.2 

197.0 

196.8 

196.6 

196.3 

196.1 

195.9 

199 

198.8 

198.6 

lilS.-l 

198.2 

198.0 

197.8 

197.6 

197.3 

197.1 

196.9 

200 

199.8 

199.6 

199.4 

199.2 

199.0 

198.8 

198.6 

198.3 

198.1 

197.9 

ALCOHOLS  AND  ACETONES 


41 


True  per  cent  of  proof  for  temperatures  between  71°  F.  and  80°  F. 


Indica- 
tion. 

71°  F. 

72°  F. 

73°  F. 

74°  F. 

75°  F. 

76°  F. 

77°  F. 

78°  F. 

79°  F. 

80°  F. 

161 

157.4 

157.0 

156.7 

156.3 

156.0 

155.6 

155.3 

154.9 

154.6 

154.2 

162 

158.4 

158.0 

157.7 

157.3 

157.0 

156.7 

156.3 

156.0 

155.6 

155  3 

163 

159.4 

159.0 

158.7 

158.3 

158.0 

157.7 

157.3 

157.0 

156.6 

156.3 

164 

160.4 

160.0 

159.7 

159.3 

159.0 

158.7 

158.3 

158.0 

157.6 

157.3 

165 

161.4 

161.1 

160.7 

160.4 

160.1 

159.8 

159.4 

159.1 

158.7 

158.4 

166 

162.4 

162.1 

161.7 

161.4 

161.1 

160.8 

160.4 

160.1 

159.7 

159.4 

167 

163.5 

163.1 

162.8 

162.4 

162.1 

161.8 

161.4 

161.1 

160.7 

160.4 

168 

164.5 

164.1 

163.8 

163.4 

163.1 

162.8 

162.5 

162.1 

161.8 

161.5 

169 

165.5 

165.2 

164.8 

164.5 

164.2 

163.9 

163.5 

163.2 

162.8 

162.5 

170 

166.5 

166.2 

165.8 

165.5 

165.2 

164.9 

164.5 

164.2 

163.8 

163.5 

171 

167.5 

167.2 

166.8 

166.5 

166.2 

165.9 

165.6 

165.2 

164.9 

164.6 

172 

168.6 

168.2 

167.9 

167.5 

167.2 

166.9 

166.6 

166.2 

165.9 

165.6 

173 

169.6 

169.3 

168.9 

166.6 

168.3 

168.0 

167.7 

167.3 

167.0 

166.7 

174 

170.6 

170.3 

169.9 

169.6 

169.3 

169.0 

168.7 

168.3 

168.0 

167.7 

175 

171.7 

171.4 

171.0 

170.7 

170.4 

170.1 

169.8 

169.4 

169.1 

168.8 

176 

172.7 

172.4 

172.0 

171.7 

171.4 

171.1 

170.8 

170.4 

170.1 

169.8 

177 

173.8 

173.5 

173.1 

172.8 

172.5 

172.2 

171.9 

171.5 

171.2 

170.9 

178 

174.8 

174.5 

174.1 

173.8 

173.5 

173.2 

172.9 

172.6 

172.0 

179 

175.8 

175.5 

175.2 

174.9 

174.6 

174.3 

174.0 

173.6 

173  '.3 

173.0 

180 

176.8 

176.5 

176.2 

175.9 

175.6 

175.3 

175.0 

174.7 

174.4 

174.1 

181 

177.9 

177.6 

177.3 

177.0 

176.7 

176.4 

176.1 

'175.8 

175.5 

175.2 

182 

178.9 

178.6 

178.3 

178.0 

177.7 

177.4 

177.1 

176.8 

176.5 

176.2 

183 

179.9 

179.6 

179.4 

179.1 

178.8 

178.5 

178.2 

177.9 

177.6 

177.3 

184 

180.9 

180.6 

180.4 

180.1 

179.8 

179.5 

179.2 

179.0 

178.7 

178.4 

185 

182.0 

181.7 

181.4 

181.1 

180.8 

180.5 

180.2 

180.0 

179.7 

179.4 

186 

183.0 

182.7 

182.5 

182.2 

181.9 

181.6 

181.3 

181.1 

180.8 

180.5 

187 

184.0 

183.8 

183.5 

183.3 

183.0 

182.7 

182.4 

182.1 

181.8 

181.5 

188 

185.1 

184.9 

184.6 

184.4 

184.1 

183.8 

183.5 

183.2 

182.9 

182.6 

189 

186.2 

186.0 

185.7 

185.5 

185.2 

184.9 

184.6 

184.4 

184.1 

183.8 

190 

187.3 

187.1 

186.8 

186.6 

186.3 

186.0 

185.8 

185.5 

185.3 

185.0 

191 

188.4 

188.1 

187.9 

187.6 

187.4 

187.1 

186.9 

186.6 

186.4 

186.1 

192 

189.4 

189.2 

188.9 

188.7 

188.4 

188.2 

187.9 

187.7 

187.4 

187.2 

193 

190.5 

190.2 

190.0 

189.7 

189.5 

189.3 

189.0 

188.8 

188.5 

188.3 

194 

191.5 

191.3 

191.0 

190.8 

190.6 

190.4 

190.1 

189.9 

189.6 

189.4 

195 

192.6 

192.3 

192.1 

191.8 

191.6 

191.4 

191.2 

190.9 

190.7 

190.5 

196 

193.6 

193.4 

193.1 

192.9 

192.7 

192.5 

192.2 

192.0 

191.7 

191.5 

197 

194.6 

194.4 

194.1 

193.9 

193.7 

193.5 

193.3 

193.0 

192.8 

192.6 

198 

195.7 

195.5 

195.2 

195.0 

194.8 

194.6 

194.4 

194.1 

193.9 

193.7 

199 

106.7 

196.5 

196.3 

196.1 

195.9 

195.7 

195.4 

195.2 

194.9 

194.7 

200 

197.7 

197.5 

197.3 

197.1 

196.9 

196.7 

196.5 

196.2 

196.0 

195.8 

42         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 


True  per  cent  of  proof  for  temperatures  between  81°  F.  and  90°  F. 


Indica- 
tion 

81°F. 

82°  F. 

83°  F. 

84°  F. 

85°  F. 

86°  F. 

87°  F. 

88°  F. 

89°  F. 

90°  F. 

161 

153.9 

153.5 

153.2 

152.8 

152.5 

152.1 

151.7 

151.4 

151  0 

150  6 

162 

154.9 

154.6 

154.2 

153.9 

153.5 

153.1 

152.8 

152  4 

152.1 

151.7 

163 

156.0 

155.6 

155.3 

154.9 

154.6 

154.2 

153.9 

153.5 

153.2 

152.8 

164 

157.0 

156.6 

156.3 

155.9 

155.6 

155.2 

154.9 

154.5 

154  2 

153  8 

165 

158.0 

157.7 

157.3 

157.0 

156.6 

156.3 

155.9 

155.6 

155.2 

154.9 

166 

159.1 

158.7 

158.4 

158.0 

157.7 

157.3 

157.0 

156.6 

156.3 

155.9 

167 

160.1 

159.7 

159.4 

159.0 

158.7 

158.4 

158.0 

157.7 

157.3 

157.0 

168 

161.1 

160.8 

160.4 

160.1 

159.7 

159.4 

159.0 

158.7 

158.3 

158.0 

169 

162.2 

161.8 

161.5 

161.1 

160.8 

160.5 

160.1 

159.8 

159.4 

159.1 

170 

163.2 

162.8 

162.5 

162.1 

161.8 

161.5 

161.1 

160.8 

160.4 

160.1 

171 

164.3 

163.9 

163.6 

163.2 

162.9 

162.6 

162.2 

161.9 

161.5 

161.2 

172 

165.3 

165.0 

164.6 

164.3 

164.0 

163.7 

163.3 

163.0 

162.6 

162.3 

173 

166.4 

166.0 

165.7 

165.3 

165.0 

164.7 

164.3 

164.0 

163.6 

163.3 

174 

167.4 

167.1 

166.7 

166.4 

166.1 

165.8 

165.4 

165.1 

164.7 

164.4 

175 

168.5 

168.2 

167.8 

167.5 

167.2 

166.9 

166.5 

166.2 

165.8 

165.5 

176 

169.5 

169.2 

168.9 

168.6 

168.3 

168.0 

167.6 

167.3 

166.9 

166.6 

177 

170.6 

170.3 

169.9 

169.6 

169.3 

169.0 

168.7 

168.3 

168.0 

167.7 

178 

171.7 

171.4 

171.0 

170.7 

170.4 

170.1 

169.8 

169.4 

169.1 

168.8 

179 

172.7 

172.4 

172.1 

171.8 

171.5 

171.2 

170.9 

170.5 

170.2 

169.9 

180 

173.8 

173.5 

173.2 

172.9 

172.6 

172.3 

172.0 

171.6 

171.3 

171.0 

181 

174.9 

174.6 

174.3 

174.0 

173.7 

173.4 

173.1 

172.7 

172.4 

172.1 

182 

175.9 

175.6 

175.3 

175.0 

174.7 

174.4 

174.1 

173.8 

173.5 

173.2 

183 

177.0 

176.7 

176.4 

176.1 

175.8 

175.5 

175.2 

174.9 

174.6 

174.3 

184 

178.1 

177.8 

177.5 

177.2 

176.9 

176.6 

176.3 

176.0 

175.7 

175.4 

185 

179.1 

178.8 

178.6 

178.3 

178.0 

177.7 

177.4 

177.0 

176.7 

176.4 

186 

180.2 

179.9 

179.6 

179.3 

179.0 

178.7 

178.4 

178.1 

177.8 

177.5 

187 

181.2 

180.9 

180.7 

180.4 

380.1 

179.8 

179.5 

179.2 

178.9 

178.6 

188 

182.3 

182.0 

181.8 

181.5 

181.2 

180.9 

180.6 

180.4 

180.1 

179.8 

189 

183.5 

183.2 

183.0 

182.7 

182.4 

182.1 

181.8 

181.5 

181.2 

180.9 

190 

184.7 

184.4 

184.1 

183.8 

183.5 

183.2 

182.9 

182.7 

182.4 

182.1 

191 

185.8 

185.5 

185.2 

184.9 

184.6 

184.3 

184.0 

183.8 

183.5 

183.2 

192 

186.9 

186.6 

186.4 

186.1 

185.8 

185.5 

185.2 

185.0 

184.7 

184.4 

193 

188.0 

187.8 

187.5 

187.3 

187.0 

186.7 

186.4 

186.2 

185.9 

185.6 

194 

189.1 

188.9 

188.6 

188.4 

188.1 

187.8 

187.6 

187.3 

187.1 

186.8 

195 

190.2 

190.0 

189.7 

189.5 

189.2 

188.9 

188.7 

188.4 

188.2 

187.9 

196 

191.3 

191.0 

190.8 

190.5 

190.3 

190.0 

189.8 

189.5 

189.3 

189.0 

197 

192.4 

192.1 

191.!) 

191.6 

191  .4 

191.2 

190.9 

190.7 

190.4 

190.2 

198 

193.5 

193.2 

193.0 

192.7 

192.5 

192.3 

192.0 

191.8 

191.5 

191.3 

199 

194.5 

194.3 

194.0 

193.8 

193.6 

193.4 

193.1 

192.9 

192.6 

192.4 

200 

195.6 

195.4 

195.1 

194.9 

194.7 

194.5 

194.2 

194.0 

193.7 

193.5 

58.  Estimation  of  methyl  alcohol  in  mixtures  with 
ethyl  alcohol.  The  method  of  Thorp  &  Holmes  given 
below  has  proven  very  satisfactory.  If  a  Zeiss  im- 
mersion refractometer  be  accessible,  the  method  of 
Leach  and  Lythgoe  J  is  to  be  preferred,  as  it  is  more 
rapid  and  convenient,  and  equally  satisfactory.  If  the 

1  J.  Am.  Chem.  Soc.,  1905,  27,  964. 


ALCOHOLS  AND  ACETONES  43 

alcoholic  mixture  to  be  examined  contains  acetone, 
acteone  oils  or  other  solvents,  it  is  advisable  to  follow 
the  method  of  Knight  and  Lincoln,  S.  Ind.  and  Eng. 
Chem.  7,  page  837. 

The  Thorp  and  Holmes  method  depends  upon  the 
fact  that  in  the  presence  of  potassium  dichromate 
and  sulphuric  acid,  in  a  closed  vessel  at  100°,  ethyl 
alcohol  is  converted  into  its  theoretical  equivalent  of 
acetic  acid,  while  with  methyl  alcohol,  the  product 
resulting  from  the  oxidation  is  always  carbon  dioxide 
and  water.  It  has,  however,  been  found  that  for 
each  gram  of  ethyl  alcohol  present  in  the  solution, 
0.01  gram  of  carbon  dioxide  may  be  formed,  and  this 
correction  should  be  made  in  all  determinations. 

The  specific  gravity  is  determined  by  means  of  a 
pycnometer.  The  total  per  cent  of  the  alcohol  is 
practically  the  same  as  the  per  cent  of  ethyl  alcohol 
of  the  same  specific  gravity. 

The  methyl  alcohol  is  determined  by  converting  it 
into  carbon  dioxide  by  means  of  sulphuric  acid  and 
potassium  dichromate  in  the  Knorrs'  apparatus. 

59.  Procedure.  Weigh  into  the  flask  20  grams  of 
potassium  dichromate,  connect  the  apparatus  after 
having  weighed  the  soda-lime  tubes.  Introduce 
through  the  stop-cock  funnel  an  exact  volume  of  the 
alcohols  not  to  exceed  4  grams  of  the  mixed  alcohols, 
and  an  amount  of  water  equal  to  50  c.c.,  less  the  num- 
ber of  c.c.  of  alcoholic  solution;  80  c.c.  of  sulphuric 
acid  (made  by  diluting  one  volume  of  concentrated 
acid  with  four  volumes  of  water)  are  added,  well 
shaken  and  allowed  to  stand  18  hours.  Dissolve 
10  grams  of  potassium  dichromate  in  50  c.c.  of  water, 
add  through  the  funnel;  then  add  50  c.c.  of  concen- 
trated sulphuric  acid  and  heat  the  contents  of  the 


44         PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

flask  to  boiling  for  about  ten  minutes,  the  carbon 
dioxide  being  carried  off  by  a  current  of  air  through 
the  apparatus.  The  heat  is  now  removed  and  the 
current  of  air  continued  for  a  few  minutes  longer. 
Disconnect  and  weigh  the  soda-lime  tubes. 

Calculate  the  methyl  alcohol  from  the  proportion 

1.373:  1 :  :  wt.  C02  obtained:  x 

x  =  wt.  methyl  alcohol, 

the  theoretical  oxidation  of  1  gram  methyl  alcohol 
producing  1.373  grams  of  carbon  dioxide. 

EXAMPLE 

Specific  gravity  of  sample 0. 7992 

Weight  of  sample  used 1 . 0118  grams 

Weight  of  carbon  dioxide 1. 3810  grams 

1.373:1:  :1.3810:x 

x  =  1 . 006  grams  methyl  alcohol. 

1.0118:  1.1006:  :  100  :  y 

y  =  99 . 4  per  cent  methyl  alcohol. 

60.  Correction.     If    ethyl    alcohol   is   present,    the 
correction  previously  referred  to,  of  0.01  gram  carbon 
dioxide  for  each  gram  of  ethyl  alcohol,  should  always 
be  applied.    The  weight  of  the  methyl  alcohol  sub- 
tracted from  the  weight  of  the  mixed  alcohols  (calcu- 
lated from  the  sp.  gr.)  gives  weight  of  the  ethyl  alco- 
hol, approximately.    The  weight  obtained  multiplied 
by  0.01  gives  correction  to  be  deducted  from  the  total 
carbon  dioxide,  for  the  recalculation  of  the  weight  of 
methyl  alcohol.     It  is  obvious  that  a  very  slight  error 
is  thus  introduced,  but  the  writer  believes  that  it  is  so 
small  that  it  may  be  safely  neglected. 

61.  Acetone   uses.     Commercially  pure  acetone  is 
not  used  to  any  extent  in  the  paint  and  varnish  indus- 
tries except  in  nitro-cellulose  lacquers.     Admixed  with 
methyl  alcohol  it  is  used  extensively  in  the  prepara- 
tion of  paint  and  varnish  removers.    The  usual  stan- 


ALCOHOLS  AND  ACETONES  45 

dard  mixtures  of  alcohol  and  acetone  used  for  this 
purpose  are  approximately  as  follows: 

1.  Acetone  25  per  cent,  methyl  alcohol  75  per  cent. 

Sp.  Gr.  approximately  0.804. 

2.  Acetone  50  per  cent,  methyl  alcohol  50  per  cent. 

Sp.  Gr.  approximately  0.807. 

This  grade  contains  from  a  trace  up  to  2  per  cent  of 
methyl  acetate. 

3.  Acetone  50  per  cent,  methyl  acetate  15  per  cent 

and  methyl  alcohol  35  per  cent. 

The  above  grades  frequently  vary  in  composition. 
The  first  grade  may  contain  methyl  acetate  up  to  6 
per  cent,  and  the  acetone  content  may  vary  from  24 
to  29  per  cent.  The  first  two  grades  may  have  specific 
gravities  as  high  as  0.823,  due  to  the  presence  of  alde- 
hyde bodies  of  unknown  composition  which  possess  a 
pungent  disagreeable  odor  and  vigorously  attack  the 
workers'  hands  when  used  in  paint  and  varnish  re- 
movers. The  specific  gravity  of  pure  methyl  alcohol 
is  0.796,  of  pure  acetone  0.797,  and  of  methyl  acetate 
0.964  at  15.5°  C. 

62.  Acetone  content,  Messinger's  method.  One  c.c. 
of  a  mixture  of  10  c.c.  of  acetone  and  90  c.c.  of  water 
is  treated  with  10  c.c.  of  twice  normal  soda  solution 
and  allowed  to  stand  5  minutes.  Then  an  accurately 
measured  portion  of  50-100  c.c.,  depending  on  the 
amount  of  acetone  present,  of  N/10  iodine  solution 
is  added  while  shaking.  The  solution  is  made  just 
acid  with  dilute  sulphuric  acid  ten  minutes  after  the 
addition  of  the  iodine  solution.  The  excess  iodine 
is  titrated  at  once  with  tenth-normal  sodium  thio- 
sulphate,  using  a  few  drops  of  starch  solution  as 


46         PAINT  VEHICLES,   JAPANS   AND  VARNISHES 

an  indicator.     The  solution  should  be  kept  at  a  tem- 
perature of  from  15°-20°  C. 
Calculation: 

X  =  grams  of  acetone  in  100  c.c.  spirit. 

Y  =  number  c.c.  of  N/10  iodine  required. 

N  =  volume  of  sample  taken  for  titration. 

y  X  0.096672 
Then  X  =  n  -     — 

The  author  has  found  that  this  method  gives  very 
satisfactory  results.  It  is  essential,  however,  that  the 
temperature  be  kept  closely  at  15°  C.  and  the  time 
limit,  of  ten  minutes,  between  the  addition  of  the 
iodine  solution  and  the  titration  with  the  thiosulphate, 
be  adhered  to,  otherwise  varying  results  will  be  ob- 
tained. Usually  it  will  be  found  more  convenient  to 
take  5  c.c.  of  the  acetone  to  be  tested,  diluting  to 
500  c.c.  and  taking  a  sample  of  this  mixture  for  the 
determination. 

63.    Methyl  acetate.1    Five  c.c.  of  the  sample  are 
run  into  a  flask,  and  ten  c.c.  normal  sodium  hydroxide 
free  from  carbonate  are  added.    The  flask  connected 
to  a  return  condenser  is  heated  and  the  contents  kept 
boiling  for  two  hours.     Instead  of  digesting  at  the 
boiling  temperature,  the  flask  may  be  allowed  to  stand 
overnight  at  room  temperature  and  then  heated  on 
the  steam  bath  for  thirty  minutes  connected  with  an 
ordinary  tube  condenser.     The  liquid  after  digestion 
is  cooled  and  titrated  with  normal   sulphuric   acid, 
using  phenolphthalein  as  an  indicator. 
Methyl  acetate  =  grams  per  100  c.c.  of  sample 
.074  X  c.c.  of  N/l  soda  soln.  required  X  100 
c.c.  of  sample  taken. 

1  Regulations  No.  30  revised,  U.  S.  Internal  Revenue,  page  46. 


ALCOHOLS  AND  ACETONES  47 

The  author  has  found  that  instead  of  boiling  with  a 
return  condenser,  the  use  of  a  pressure  flask  heated 
for  thirty  minutes  in  boiling  water  gives  more  uni- 
form results. 

64.  Acetone  oils.  In  the  manufacture  of  wood  alco- 
hol and  acetone,  a  number  of  higher  ketones  are  ob- 
tained. These  are  purified  by  distillation  and  put  on 
the  market  as  mixtures  having  definite  distilling 
ranges.  They  are  used  chiefly  in  the  manufacture  of 
special  varnishes  and  lacquers.  They  have  a  strong, 
pungent,  characteristic  odor,  disagreeable  to  most 
people.  Their  solvent  value  is  very  high,  having  a 
much  slower  rate  of  evaporation  and,  consequently,  a 
longer  flow  than  other  lacquer  solvents,  except  fusel 
oil.  They  have  found  a  wide  use  in  brushing  and  clip- 
ping lacquers  where  large  surfaces  are  to  be  finished. 
Usually  amyl  acetate,  which  is  almost  always  present 
in  these  lacquers,  masks  the  odor  of  the  heavy  acetone 
distillates  to  a  considerable  degree. 

In  addition  to  acetone  and  hydrocarbons,  the  fol- 
lowing substances  have  been  identified  in  acetone  oils: 
Methyl  ethyl  ketone  (b.  pt.  79.6°  C.),  methyl  propyl 
ketone  (101.7°),  methyl  isopropyl  ketone  (94°),  methyl 
n-butyl  ketone  (127.4°),  cyclopentanone  (130°),  and 
acetaldehyde  (20.8°).  All  these  substances,  with  the 
exception  of  the  hydrocarbons,  are  soluble  in  sodium 
bisulphate  solutions. 


48         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

TABLE  IX 
65.  Distillation  of  acetone  oils  by  the  author 

ill 


2.5 
4.5 

99.5 
16.5 
17.5 
17.0 
9.0 
8.5 
5.0 
4.0 
6.0 


Temperature 

I 

II 

60-70°  C  

6.5 

6.0 

70-80  

35.0 

25.0 

80-90  

53.0 

28.0 

90-100  

5.0 

18.5 

100-110  

8.5 

110-120  

4.5 

120-130  

6.0 

130-140  

3.0 

140-150  

0.5 

150-160  

160-170 

170-180 

180-190 

190-200 

200-210  

210-220  

Residue  -. 

CHAPTER  V 

BENZOL  AND  SOLVENT  NAPHTHAS 

66.  Uses.     In   the   paint   and   varnish   industries, 
benzol  finds  its  chief  use  in  paint  and  varnish  removers 
on  account  of  its  high  solvent  properties,  and  in  stains 
to  secure  proper  penetration.     The  solvent  naphthas 
are  used  in   enamel   liquids   and  baking  Japans  to 
prevent  "  flooding  "  and  to  secure  the  desired  "flow  " 
as  well  as  for  their  great  solvent  strength.     These 
benzol  products  should  be  water-white  and  free  from 
a  disagreeable    odor    either  in  the  sample  or  after 
evaporation  from  a  sheet  of  filter  paper. 

67.  Specific  gravity.     The  specific  gravities  of  the 
more  commonly  used  benzol  products  are  as  follows: 

Commercially  pure  benzol 0. 875  to  0.885 

100%  benzol 875  to    .885 

90%  benzol 870  to    .882 

Solvent  naphtha 862  to    .  872 

Hi-flash  naphtha 870  to    .880 

The  specific  gravity  may  be  determined  at  room 
temperature  and  calculated  to  15.5°  C.  by  using  the 
coefficient  of  expansion  for  benzol,  which  is  0.00066 
per  degree  Centigrade. 

68.  Distillation.     The    designation    "90%   benzol" 
means  that  90  per  cent  of  the  entire  product  will  dis- 
till under   100°  C.     It   is   this  grade  which  is  most 
widely   used   in   the   paint   industry.    The  following 
method  of  distillation  is  the  one  used  by  one  of  the 
large  producers  of  benzol  products  and  has  been  found 
very  satisfactory  by  the  author. 


50         PAINT  VEHICLES,   JAPANS   AND  VARNISHES 

69.  Procedure.     The  flask  used  for  this  distillation 
has  a  capacity  of  200  c.c.,  the  side  tube  being  at  the 
center  of  the  neck.     One  hundred  c.c.  of  the  material 
is  placed  in  the  distilling  flask  and  a  thermometer  in- 
serted so  that  the  top  of  its  bulb  is  on  a  level  with  the 
bottom  of  the  side  tube.    The  flask  should  be  placed 
on  an  asbestos  mat,  through  which  a  hole  has  been 
cut  one  inch  in  diameter,  and  heat  applied  direct  from 
a  Bunsen  burner.     The  asbestos  mat  prevents  super- 
heating to  a  great  extent.    The  operator  should  be 
careful  to  remove  the  source  of  heat  as  soon  as  the 
last  drop  of  liquid  has  vaporized.    The  distillation 
should  be  started  slowly,  finished  slowly,  and  carried 
on  at  a  rate  which  should  be  judged  by  the  manner  in 
which  the  drops  of  condensed  vapors  are  coming  from 
the  delivery  end  of  the  condenser  tube.     During  the 
major  part  of  the  distillation,  it  should  be  run  at  a 
rate  which  will  just  allow  individual  and  separate 
drops  to  be  formed.    A  steady  stream  should  at  no 
time  flow  from  the  end  of  the  condenser  tube.    The 
starting  point  should  be  noted  and  volume  readings 
taken  every  even  10°  until  the  liquid  is  all  distilled. 

70.  Solvent    naphtha    and    the    higher    flash-point 
naphthas.   These  solvents  are  mixtures  of  toluol,  xyols, 
and   the  higher  boiling  point  homologues  of  benzol. 
They  act  as  very  powerful  solvents,  especially  toward 
the  more  difficultly  soluble  blacks  used  in  high  grade 
baking  Japans.     Occasionally,  crude  coal  tar  naphthas 
are  used  in  the  cheaper  baking  Japans.    Such  naphthas 
distill  essentially  above  200°  C.  and  usually  contain  a 
considerable  percentage  of  naphthalene  which  crystal- 
lizes out  in  cold  weather.     These  crudes  are  sold  at  a 
low  price  and  frequently  contain  water  which  must  be 
removed  by  settling  before  they  can  be  added  to  the 


BENZOL  AND  SOLVENT   NAPHTHAS 


51 


hot  Japan.  Particular  pains  are  therefore  necessary 
in  sampling  shipments  of  these  crudes  ,in  order  to 
obtain  a  uniform  sample  if  water  be  present. 

TABLE  X 
71.  Distillation  of  refined  solvent  naphthas 


130°C.-140°C 

140°  -150° 

150°  -160° 

-170° 

-180° 

-190° 

-200° 

-210°. . . 


170° 
180° 
190° 
200° 


Solvent  Naphtha  Hi-flash 

I                     II  I 

2.1  9.3 

72.4  54.1  1.5 

12.1  24.5  16.5 

5.8           8.5  29.2 

4.5           3.6  18.8 

2.0  ....  17.5 

1.1  14.5 

....  ....  2.0 

100.0  100.0  100.0 


Naphtha 
II 

19. 5 
26.5 
21.8 
13.5 
13.4 
3.5 

T.8 

100.0 


72.  Evaporation.  The  comparative  evaporation 
rates  of  various  benzol  products  are  shown  in  the  fol- 
lowing table,  XI,  2  c.c.  of  each  material  having  been 
allowed  to  evaporate  from  a  metal  surface  3£  inches 
square  under  similar  conditions. 

TABLE  XI 


Pure  benzol                                     10    min 

utes 

100%  benzol                                     

.     13* 

90%  benzol                                          .  .  . 

14* 
107 

205 

Turpentine.  . 

.   142 

62°  naphtha 18 


CHAPTER  VI 

LINSEED  OIL 

73.  Uses.     Linseed  oil,  either  raw  or  treated,  con- 
stitutes the  major  portion  of  the  vehicle  of  nearly  all 
paints  and  is  a  most  important   constituent  of  the 
vehicle    in    most    enamels    and    varnishes.     Unfortu- 
nately, the  specifications  under  which  raw  linseed  oil 
is  purchased,  including  those  so  far  adopted  by  the 
American  Society  for  Testing  Materials,  govern  the 
purity  of  the  oil  rather  than  the  quality.     Linseed  oil 
obtained  direct  from  the  crusher  will,  invariably,  be 
found  on  examination  to  be  pure,  but  the  quality  may 
be  unsatisfactory  to   the  paint   manufacturer.     This 
may  be  due  to  the  presence  of  excessive  amounts  of 
"  foots  "  or  to  the  character  of  the  seed  from  which  the 
oil  is  obtained,  or  both.     The  determination  of  the 
oxygen  absorption  as  described  in  section   197  fre- 
quently gives  valuable  information  regarding  the  dry- 
ing value  of  an  oil  of  questionable  purity  or  suitability. 

74.  Raw   linseed   oil.     The   American   Society   for 
Testing  Materials    has    adopted    standard    specifica- 
tions for  the  purity  of  raw  linseed  oil  from  North 
American  seed  which  are  as  follows: 

Maximum  Minimum 

Specific  gravity  at  ^-|H  C 0. 936  0. 932 

lo.  o 
or 

oc   n° 

Specific  gravity  at  ~^0  C 0. 931  0. 927 

Acid  number 6.00  

Saponification  number 195.00  189.00 

Unsaponifiable  matter,  per  cent. ...  1. 50  .... 

•     Refractive  index  at  25° 1 . 4805  1 . 479 

Iodine  number  (Hanus) 180. 00 

52 


LINSEED   OIL 


53 


Commercial  shipments  of  raw  linseed  oil  from  a  good 
grade  of  North  American  seed  will,  as  a  rule,  meet 
these  specifications,  whereas  oil  from  South  American 
and  other  foreign-grown  flaxseed  very  often  will  not, 
as  indicated  by  the  following  table,  No.  XII. 

TABLE  XII 
76.  Constants  for  raw  linseed  oil 


Specific 
Gravity 
15.5° 
15.  5°  ^ 

Acid 
No. 

Iodine 
Number 
Hanus 

Saponi- 
fication 

Refrac- 
tive 
Index 
25°  C. 

Linseed  oil  from  high  grade 
North  Dakota  seed,  48 
samples  l 

9331 

0  95 

185   9 

191  3 

1  4796 

Maximum  
Minimum  
Linseed  oil  from  immature 
North   Dakota  seed,  4 
samples  * 
Average  
Maximum  
Minimum 

.9345 
.9310 

.9325 
.9336 
.9310 

3.10 
0.38 

1.78 
2.80 
0.54 

193.1 
171.6 

183.2 
185.9 
175.9 

192.9 
189.9 

192.3 
192.6 
191.9 

1.4805 

1.4788 

1.4795 
1.4801 
1.4787 

Linseed  oil  from  damp  and 
moldy  North    Dakota 
seed,  10  samples  1 
Average  
Maximum  
Minimum  
Linseed     oil     from     South 
American  seed  2 
1  
2 

.9331 
.9345 
.9315 

.9326 
.9315 

1.89 
2.97 
1.22 

1.47 
3.54 

183.1 

186.4 
175.8 

170.8 
172.3 

191.9 
193.0 
190.0 

191.4 
190.5 

1.4795 
1.4802 
1.4785 

1.4785 

1.4784 

3 

9329 

5  48 

179.2 

192.4 

1.4796 

4 

9333 

6  34 

179.0 

191.4 

1.4795 

5  

.9334 

3.91 

180.3 

190.5 

1.4796 

Linseed   oil  from   Bombay 
seed  2  
Linseed  oil  from  Calcutta 
seed2 
1  
2  
3  

.9336 

.9334 
.9334 
.9330 

1.22 

1.26 
2.02 
1.63 

179.5 

178.  5 
176.7 

177.8 

192.6 

191.9 
192.1 
191.9 

1.4794 

1  .  4792 
1.4790 
1.4791 

1  Washburn,  Bulletin  118  N.  D.  Exp.  Station,  1916. 

2  Proceedings  Am.  Soc.  for  Testing  Materials,  Vol.  XIII,  page  376. 


54         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

76.  South   American   seed.     Much  of  the  trouble 
experienced   by  eastern   paint  manufacturers  during 
recent  years  has  been  laid  to  the  use  of  oil  from  South 
American   seed.     Samples    examined   by   the   author 
have   contained   excessive   amounts   of  foots  and  in 
practice  have  been  slow  in  drying  with  the  normal 
amount  of  drier  used  in  high  grade  paints. 

77.  Methods  of  testing  prescribed  by  the  American 
Society   for    Testing    Materials.     General.     All    tests 
shall  be  made  on  oil  which  has  been  filtered  at  a  tem- 
perature of  between  60°  and  80°  F.  through  paper  in 
the  laboratory  immediately  before  weighing  out.     The 
sample  should  be  thoroughly  agitated  before  the  re- 
moval of  a  portion  for  filtration  or  analysis. 

78.  Specific    gravity.     Use    a    pycnometer,    accu- 
rately standardized  and  having  a  capacity  of  at  least 
25  c.c.,  or  any  other  equally  accurate  method,  making 
a  test  at  15.5°  C.,  water  being  1  at  15.5°  C.,  or  a  test 
at  25°  C.,  water  being  1  at  25°  C. 

The  author  has  found  it  more  satisfactory  to  use  a 
Tagliabue  hydrometer  reading  from  .900  to  .960,  ob- 
taining the  gravity  at  room  temperature  and  calculat- 
ing to  15°  C.  with  the  aid  of  the  following  table, 
No.  XIII.1 

1  Technologic  Paper  No.  9,  Bureau  of  Standards,  page  20. 


LINSEED   OIL 


55 


TABLE  No.  XIII 
79.  Density  of  linseed  oil 


Tem- 
pera- 
ture 

Density 

°C 

10 

0.  9329 

0.  9339 

0.9349 

0.9359 

0.9369 

0.9379 

0.9389 

11 

.9322 

.  9332 

.9342 

.9352 

.9362 

.9372 

.9382 

12 

.9315 

.9325 

.9335 

.9345 

.9355 

.9365 

.9375 

13 

.9308 

.9318 

.9328 

.9338 

.9348 

.9358 

.9368 

14 

.9301 

.9311 

.9321 

.9331 

.9341 

.9351 

.9361 

15 

.9294 

.9304 

.9314 

.9324 

.  9334 

.9344 

.9354 

16 

.9288 

.9298 

.9308 

.9318 

.9328 

.9338 

.9348 

17 

.9281 

.9291 

.9301 

.9311 

.9321 

.9331 

.9341 

18 

.9274 

.9284 

.9294 

.9304 

.9314 

.9324 

.9334 

19 

.9267 

.9277 

.9287 

.9297 

.9307 

.9317 

.9327 

20 

.9260 

.9270 

.9280 

.9290 

.9300 

.9310 

.9320 

21 

.9253 

.9263 

.9273 

.9283 

.9293 

.9303 

.9313 

22 

.9246 

.9256 

.9266 

.9276 

.9286 

.9296 

.9306 

23 

.9239 

.9249 

.9259 

.9269 

.9279 

.9289 

.9299 

24 

.9233 

.9243 

.9253 

.9263 

.9273 

.9283 

.9293 

25 

.9226 

.9236 

.9246 

.9256 

.9266 

.9276 

.9286 

26 

.9219 

.9229 

.9239 

.9249 

.9259 

.9269 

.9279 

27 

.9212 

.9222 

.9232 

.9242 

.9252 

.9262 

.9272 

28 

.9205 

.9215 

.9225 

.9235 

.9245 

.9255 

.9265 

29 

.9198 

.9208 

.9218 

.9228 

.9239 

.9248 

.9258 

30 

.9192 

.9202 

.9212 

.9222 

.9232 

.9242 

.9252 

31 

.9185 

.9195 

.9205 

.9215 

.9225 

.9235 

.9245 

32 

.9178 

.9188 

.9198 

.9208 

.9218 

.9228 

.9238 

33 

.9171 

.9181 

.9191 

.9201 

.9211 

.9221 

.9231 

34 

.9164 

.9174 

.9184 

.9194 

.9204 

.9214 

.9224 

35 

.9157 

.9167 

.9177 

.9187 

.9197 

.9207 

.9217 

36 

.9150 

.9160 

.9170 

.9180 

.9190 

.9200 

.9210 

37 

.9144 

.9154 

.9164 

.9174 

.9184 

.9194 

.9204 

38 

.9137 

.9147 

.9157 

.9167 

.9177 

.9187 

.9197 

39 

.9130 

.9140 

.9150 

.9160 

.9170 

.9180 

.9190 

40 

.9123 

.9133 

.9143 

.9153 

.9163 

.9173 

.9183 

56         PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

80.  Acid  number.     Expressed  in  milligrams  of  KOH 
per  gram  of  oil.     Weigh  20  grams  of  fat  or  oil  into  a 
flask,  add  50  c.c.  of  95  per  cent  alcohol  which  has 
been  neutralized  with  weak  caustic  soda,  using  phe- 
nolphthalein  as  indicator,  and  heat  to  the  boiling  point. 
Agitate  the  flask  thoroughly,  in  order  to  dissolve  the 
free  fatty   acid   as   completely   as   possible.     Titrate 
with  tenth-normal  alkali,  agitating  thoroughly,  until 
the  pink  color  persists  after  vigorous  shaking. 

Express  results  either  as  percentage  of  oleic  acid,  as 
acid  degree  (cubic  centimeters  of  normal  alkali  re- 
quired to  neutralize  the  free  acids  in  100  grams  of  oil 
or  fat),  or  as  acid  value  (milligrams  of  potassium 
hydroxide  required  to  saturate  the  free  acids  in  1  gram 
of  fat  or  oil) . 

(One  c.c.  of  tenth-normal  alkali  =  0.0282  gram  of 
oleic  acid.) 

81.  Saponification     number.     Expressed     as     with 
acid   number.     Blanks   should  also   be  run   to  cover 
effect  of  alkali  in  glass. 

(a)  Preparation  of  reagents 

(1)  Standard    sodium    hydroxide    solution.  •  Use    a 
tenth-normal    solution    of    sodium    hydroxide.     Each 
cubic    centimeter    contains   0.0040    gram   of   sodium 
hydroxide   and   neutralizes   0.0088   gram  of    butyric 
acid. 

(2)  Alcoholic  potash  solution.    Dissolve  40  grams  of 
chemically  pure  potassium  hydroxide  in  1  liter  of  95 
per  cent  redistilled  alcohol.1    The  solution  must  be 
clear  and  the  potassium  hydroxide  free  from  carbonates. 

1  The  alcohol  should  be  redistilled  from  potassium  hydroxide  on 
which  it  has  been  standing  for  some  time,  or  with  which  it  has  been 
boiled  for  some  time,  using  a  reflux  condenser. 


LINSEED   OIL  57 

(3)  Standard   acid  solution.     Prepare   accurately   a 
half-normal  solution  of  hydrochloric  acid. 

(4)  Indicator.     Dissolve  1  gram  of  phenolphthalein 
in  100  c.c.  of  95  per  cent  alcohol. 

(6)  Determination 

Conduct  the  saponification  in  a  wide-mouth  Erlen- 
meyer  flask  holding  from  250  to  300  c.c.  Clean 
thoroughly  by  washing  with  water,  alcohol,  and 
ether,  wipe  perfectly  dry  on  the  outside  and  heat  for 
one  hour  at  the  temperature  of  boiling  water;  allow 
to  cool  and  weigh. 

Run  in  about  5  grams  of  the  filtered  melted  fat  by 
means  of  a  pipette,  and  after  cooling  again  weigh  the 
flask  and  contents.  Pipette  50  c.c.  of  the  alcoholic 
potash  solution  into  a  flask  by  allowing  it  to  drain 
for  a  definite  time.  Connect  the  flask  with  a  reflux 
condenser  and  boil  for  30  minutes  or  until  the  fat  is 
completely  saponified.  Cool  and  titrate  with  half- 
normal  hydrochloric  acid,  using  phenolphthalein  as 
indicator.  The  Koettstorfer  number  (milligrams  of 
potassium  hydroxide  required  to  saponify  1  gram  of 
fat)  is  obtained  as  follows:  Subtract  the  number  of 
cubic  centimeters  of  hydrochloric  acid  used  to  neu- 
tralize the  excess  of  alkali  after  saponification,  from 
the  number  of  cubic  centimeters  necessary  to  neutral- 
ize the  50  c.c.  of  alkali  added;  multiply  the  result  by 
28.06  (the  number  of  milligrams  of  potassium  hy- 
droxide per  cubic  centimeter)  and  divide  by  the  num- 
ber of  grams  of  fat  used.  Conduct  two  or  three 
blank  experiments,  using  the  same  pipette  and  draining 
for  the  same  length  of  time. 

82.  Unsaponifiable  Matter.  Follow  Boemer's 
method  taken  from  his  "Ubbelohde  Handbuch  der  Ole 


58        PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

u.  Fette,"  pages  261-262.  "  To  100  g.  of  oil  in  a  1000- 
to  1500-c.c.  Erlenmeyer  flask  add  60  c.c.  of  an  aque- 
ous solution  of  potassium  hydroxide  (200  g.  KOH 
dissolved  in  water  and  made  up  to  300  c.c.)  and  140 
c.c.  of  95  per  cent  alcohol.  Connect  with  a  reflux 
condenser  and  heat  on  the  water  bath,  shaking  at  first 
until  the  liquid  becomes  clear.  Then  heat  for  one 
hour  with  occasional  shaking.  Transfer  while  yet 
warm  to  a  2000-c.c.  separatory  funnel  to  which  some 
water  has  been  added,  wash  out  the  Erlenmeyer  with 
water,  using  in  all  600  c.c.  Cool,  add  800  c.c.  of  ether 
and  shake  vigorously  one  minute.  In  a  few  minutes 
the  ether  solution  separates  perfectly  clear.  Draw  off 
the  soap  and  filter  the  ether  (to  remove  last  traces  of 
soap)  into  a  large  Erlenmeyer  and  distill  off  the  ether, 
adding  if  necessary  one  or  two  pieces  of  pumice  stone. 
Shake  the  soap  solution  three  times  with  400  c.c.  of 
ether,  which  add  to  the  first  ether  extract.  To  the 
residue  left  after  distilling  the  ether  add  3  c.c.  of  the 
above  KOH  solution  and  7  c.c.  of  the  95  per  cent 
alcohol,  and  heat  under  reflux  condenser  for  10 
minutes  on  the  water  bath.  Transfer  to  a  small 
separatory  funnel,  using  20  to  30  c.c.  of  water,  and 
after  cooling  shake  out  with  two  portions  of  100  c.c. 
of  ether;  wash  the  ether  three  times  with  10  c.c.  of 
water.  After  drawing  off  the  last  of  the  water,  filter 
the  ethereal  solution  so  as  to  remove  the  last  drops 
of  water,  distill  off  the  ether,  dry  residue  in  water  oven 
and  weigh." 

83.  Refractive  index.    Use  a  properly  standardized 
Abbe  Refractometer  at  25°  C.,  or  any  other  equally 
accurate  instrument. 

84.  Iodine   number   (Hanus).      (a)    Preparation  ff 
reagents.     (1)    Hanus  iodine  solution.    Dissolve   13.2 


LINSEED   OIL  59 

grams  of  iodine  in  1000  c.c.  of  glacial  acetic  acid 
(99.5  per  cent)  showing  no  reduction  with  bichromate 
and  sulphuric  acid;  add  enough  bromine  to  double 
the  halogen  content  determined  by  titration  —  3  c.c. 
of  bromine  is  about  the  proper  amount.  The  iodine 
may  be  dissolved  by  the  aid  of  heat,  but  the  solution 
should  be  cold  when  bromine  is  added. 

(2)  Decinormal  sodium   thiosulphate   solution.     Dis- 
solve 24.8  grams  cf  chemically  pure  sodium  thiosul- 
phate, freshly  pulverized  as  finely  as  possible  and  dried 
between  filter  or  blotting  paper,  and  dilute  with  water 
to  1  liter  at  the  temperature  at  which  the  titrations 
are  to  be  made. 

(3)  Starch  paste.    Boil  1  gram  of  starch  in  200  c.c. 
of  distilled  water  for  ten  minutes  and  cool  to  room 
temperature. 

(4)  Solution    of    potassium    iodide.     Dissolve    150 
grams  of  potassium  iodide  in  water  and  make  up  1 
liter. 

(5)  Decinormal      potassium      bichromate.    Dissolve 
4.9083  grams  of  chemically  pure  potassium  bichro- 
mate in  distilled  water  and  make  the  volume  up  to  1 
liter  at  the  temperature  at  which  the  titrations  are  to 
be  made.     The  bichromate  solution  should  be  checked 
against  pure  iron. 

(6)  Determination 

(1)  Standardizing  the  sodium  thiosulphate  solution. 
Place  20  c.c.  of  the  potassium  bichromate  solution,  to 
which  have  been  added  10  c.c.  of  the  solution  of  potas- 
sium iodide,  in  a  glass-stoppered  flask.  Add  to  this 
5  c.c.  of  strong  hydrochloric  acid.  Allow  the  solu- 
tion of  sodium  thiosulphate  to  flow  slowly  into  the 
flask  until  the  yellow  color  of  the  liquid  has  almost 


60         PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

disappeared.  Add  a  few  drops  of  the  starch  paste, 
and  with  constant  shaking  continue  to  add  the  so- 
dium thiosulphate  solution  until  the  blue  color  just 
disappears. 

(2)  Weighing    the    sample.    Weigh    about    one-half 
gram  of  fat  or  0.250  gram  of  oil 1  on  a  small  watch 
crystal  or  in  some  other  suitable  way.    Melt  the  fat, 
mix  thoroughly,  pour  onto  the  crystal,  and  allow  to 
cool.     Introduce  the  watch  crystal  into  a  wide-mouth 
16-ounce  bottle  with  ground-glass  stopper. 

(3)  Absorption  of  iodine  in  Hubl's  method.    Dissolve 
the  fat  or  oil  in  the  bottle  in  10  c.c.  of  chloroform. 
After  complete  solution  has  taken  place,  add  30  c.c. 
of  the  iodine  solution  in  the  case  of  fats,  or  from  40 
to  50  c.c.2  in  the  case  of  oils.     Place  the  bottle  in  a 
dark  place  and  allow  to  stand,  with  occasional  shak- 
ing, for  three  hours.3    This  time  must  be  closely  ad- 
hered to  in  order  to  get  good  results.     The  excess  of 
iodine  should  be  at  least  as  much  as  is  absorbed. 

(4)  Absorption  of  iodine  in    Hanus  method.    Add 
25  c.c.  of  the  iodine  solution  to  the  chloroform  solu- 
tion of  the  fat.    Allow  to  stand,  with  occasional  shak- 
ing, for  thirty  minutes.     The  excess  of  iodine  should 
be  at  least  60  per  cent  of  the  amount  added. 

(5)  Titration  of  the  unabsorbed  iodine.    Add  10  c.c. 
of  the  potassium  iodide  solution  in  the  Hanus  method 
or  20  c.c.  in  the  Hubl  method  and  shake  thoroughly; 

1  Use  from  0.100  to  0.200  gram  in  the  case  of  drying  oils  which 
have  a  very  high  absorbent  power. 

2  F.  Ulzer  (J.  Soc.  Chem.  Ind.,  1898,  17 : 276)  says  iodine  should 
be  in  excess,  about  twice  the  amount  that  is  absorbed.     The  solution 
loses  strength  with  age,  but  can  be  used  as  long  as  35  c.c.  of  tenth- 
normal  thiosulphate  neutralize  25  c.c.  of  iodine  solution. 

3  The  time  allowed  does  not  give  the  complete  iodine  absorption 
power  of  an  oil  or  fat   and  cannot   be  compared  with  determination 
in  which  six  to  twelve  hours  have  been  used.     It  gives  very  satisfac- 
tory comparative  results,  but  the  time  factor  must  be  very  closely 
observed. 


LINSEED  OIL  61 

then  add  100  c.c.  of  distilled  water  to  the  contents  of 
the  bottle,  washing  down  any  free  iodine  that  may  be 
noted  on  the  stopper.  Titrate  the  iodine  with  shak- 
ing, until  the  yellow  color  of  the  solution  has  almost 
disappeared.  Add  a  few  drops  of  starch  paste  and 
continue  the  titration  until  the  blue  color  has  entirely 
disappeared.  Toward  the  end  of  the  reaction  stopper 
the  bottle  and  shake  violently,  so  that  any  iodine 
remaining  in  solution  in  the  chloroform  may  be  taken 
up  by  the  potassium  iodide  solution. 

(6)  Standardizing  the  iodine  solution  by  thiosul- 
phate  solution.  At  the  time  of  adding  the  iodine 
solution  to  the  fat  employ  two  bottles  of  the  same 
size  as  those  used  for  the  determination  for  conducting 
the  operation  described  under  paragraphs  (3),  (4)  and 
(5),  but  without  the  presence  of  any  fat.  In  every 
other  respect  the  performance  of  the  blank  experi- 
ments should  be  just  as  described.  These  blank 
experiments  must  be  made  each  time  the  iodine  solu- 
tion is  used.  Great  care  must  be  taken  that  the 
temperature  of  the  solution  does  not  change  during 
the  time  of  the  operation,  as  acetic  acid  and  alcohol 
have  very  high  coefficients  of  expansion,  and  a  slight 
change  of  temperature  makes  an  appreciable  difference 
in  the  strength  of  the  solution. 

Per  cent  of  iodine  absorbed: 

Weight  of  fat  taken gram  0. 250 

Quantity  of  iodine  solution  used c.c.  40. 0 

Thiosulphate  equivalent  to  iodine  used c.c.  65.0 

Thiosulphate  equivalent  to  remaining  iodine c.c.  40.0 

Thiosulphate  equivalent  to  iodine  absorbed c.c.  25.0 

Per  cent  of  iodine  absorbed  (25.0  X  0.012692  X  100) 
divided  by  0.250  =  126.92. 

85.  Foots.  The  paint  specifications  adopted  by 
the  U.  S.  Navy,  by  most  of  the  public  service  cor- 


62         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

porations,  and  by  many  of  the  larger  railroad  systems, 
require  that  the  linseed  oil  used  be  properly  aged, 
well  settled,  and  free  from  foots.  Gardner  (J.  Ind. 
and  Eng.  Chem.,  Sept.  1916)  vigorously  condemns  the 
use  of  freshly  pressed  oil  containing  foots  in  the  manu- 
facture of  high  grade  paints. 

Practically  all  shipments  of  commercial  raw  linseed 
oil  contain  foots,  frequently  in  excessive  quantities, 
and  the  only  recourse  the  paint  manufacturer  has  is 
to  settle  his  oil  in  tanks  until  it  is  substantially  freed 
from  foots,  an  operation  which  involves  considerable 
expense  and  wastage.  It  is  the  experience  of  the 
author  that  paints  containing  appreciable  quantities 
of  foots  very  frequently  give  serious  trouble  when 
used  where  the  service  requirements  are  such  as  to 
necessitate  the  use  of  a  strictly  high  grade  paint. 

86.  Estimation.     Two  methods  have  been  devised, 
one  by  Walker  and  Wertz  and  the  other  by  the  author, 
to  determine  the  comparative  amount  of  foots  in  lin- 
seed oil. 

87.  Walker  and   Wertz   method.     Prepare  a  solu- 
tion of  calcium  chloride  saturated  at  room  tempera- 
ture.   To  this  add  10  per  cent  by  volume  of  concen- 
trated  hydrochloric    acid.    Mix    thoroughly    25    c.c. 
each  of  oil  and  acetone  and  10  c.c.  of  the  acid  calcium 
chloride  and  pour  into  a  graduated  tube  to  settle. 
All  should  be  at  room  temperature. 

Pickard  l  in  the  following  table  (XIV)  records  the 
results  obtained  by  applying  this  test  to  representa- 
tive shipments  of  raw  oil  made  by  several  oil  pro- 
ducers, the  other  analytical  constants  being  included 
as  of  interest  in  connection  with  the  percentage  of 
foots. 

i  Proceedings  A.  S.  T.  M.,  Vol.  XVII,  Part  1,  page  380. 


LINSEED   OIL  63 

TABLE  XIV 

88.  Analytical  constants  of  raw  linseed  oil 

NORTH   AMERICAN   SEED 
Specific^  Gravity 

15". 5  Iodine  Number       Acid  Number     Foots,  Per  Cent 

at  15^5  0< 

0.9345       186.9        2.0  3.2 

0.9358       189.8        1.2  0.4 

0.9342       187.9        1.4  0.4 

0.9348       182.0        2.3  1.6 

0.9345       186.9        0.8  2.0 

0.9348       189.2        1.0  0.8 

0.9338       187.5        2.2  0.4 

0.9349       186.1        0.8  2.0 

0.9340       185.7        2.0  4.0 

0.9341       187.2        2.2  1.5 

0.9347       187.2        2.0  1.2 

0.9347       184.4        2.3  2.0 

0.9346       184.8        2.3  1.2 

0.9344       182.4        3.2  2.0 

0.9343       183.4        4.0  2.8 

0.9343       183.8        3.1  3.6 

0.9346       184.5        1.8  1.0 

0.9347       183.3        2.4  2.5 

0.9346       185.2        2.4  1.6 

0.9344       184.3        2.9  2.0 

0.9342       184.4        2.1  1.6 

0.9342       186.4        1.7  0.8 

0.9343       185.3        0.9  0.4 

0.9341       188.3        1.9  3.6 

0.9340       185.7        1.7  1.6 

0.9345       186.8        0.5  0.8 

0.9346       186.6        1.1  1.6 

SOOTH  AMERICAN   SEED 

0.9326       173.2        4.0  2.8 

0.9326       176.1        2.6  3.2 

0.9323       176.0        4.2  2.8 

0.9327       175.6        4.0  3.6 

0.9326       174.9        4.0  4.0 

0.9318       175.3        2.1  2.4 

0.9327       175.1        3.4  2.8 

0.9322       176.5        2.1  4.0 

89.  Author's    method.    The    method    devised    by 
the  author  1  depends  on  the  precipitation  of  the  foots 
by  shaking  100  c.c.  of  syrupy  phosphoric  acid  and 
100  c.c.  oil,  thinning  with  150  c.c.  naphtha  and  allow- 

1  Drugs,  Oils  and  Paints,  July,  1916,  page  51. 


64         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

ing  the  foots  to  collect  in  the  calibrated  neck  of  a 
suitable  flask,  keeping  the  temperature  at  approxi- 
mately 30°  C.  during  the  operation. 

Oils,  fresh  from  the  filter  press,  gave  volume  read- 
ings of  4  to  5  per  cent ;  the  same  oils  after  settling  for 
3  months  showed  about  0.1  per  cent  foots.  The 
author  has  examined  commercial  shipments  having 
as  high  as  6  per  cent  foots. 

90.  Composition  of  linseed  oil  foots.1  The  foots 
from  linseed  oil,  manufactured  by  the  naphtha  extrac- 
tion process,  after  centrifuging,  contained  75.8  per 
cent  linseed  oil,  the  extraction  being  conducted  with 
carbon  disulphide.  The  insoluble  portion  contained: 

Per  cent 

SiO2 • 34.38 

CaO 7.98 

MgO 8.39 

P2O5 46.50 

K2O Present 

97.25 

The  foots  from  an  hydraulic  pressed  linseed  oil 
contained: 

Per  cent 

SiO2 None 

CaO 3.26 

MgO 4.99 

K20 10.27 

P2O5 81.08 

99.60 
1  Eisenschyml,  J.  Ind.  and  Eng.  Chem.,  January,  1910. 


CHAPTER  VII 

LINSEED   OIL   (Continued) 

91.  Determination  of  hexabromide  number  of  lin- 
seed oil  fatty  acids.1     G.  W.  Thompson  considers  the 
method  given  below  as  very  satisfactory  for  deter- 
mining the  purity  of  linseed  oil. 

The  determination  of  the  hexabromide  number  is 
preceded  by  the  preparation  of  free  fatty  acids. 

92.  Preparation    of    pure    linseed    oil    fatty    acids. 
Three  and  one-half  grams  of  the  linseed  oil  are  weighed 
into  each  of  three  round-bottom  evaporating  dishes  of 
about  220  c.c.   capacity.     Then  45  c.c.   of  one-half- 
normal  alcoholic  potash  are  added  in  each  case  and 
the  dishes  are  placed  on  the  water  bath.     This  is 
brought    slowly    to    boiling.     The    oil    is    frequently 
stirred  with  a  glass  rod,  flattened  at  the  end.     By 
this  method,   the  saponification  is  better  and  more 
quickly  accomplished. 

The  alcoholic  potash  is  prepared  as  follows:  28  g. 
of  solid  pure  caustic  alkali  are  placed  in  a  1 -liter 
measuring  cylinder  and  dissolved  hi  from  30  to  40  c.c. 
of  distilled  water;  then  97  per  cent  ethyl  alcohol  is 
added,  to  make  the  volume  1  liter.  The  solution  is 
allowed  to  stand  for  2  or  3  days  to  settle  out  any 
cloudiness  due  to  potassium  carbonate.  This  potash 
solution  is  best  kept  in  a  brown  bottle,  stoppered  with 
a  rubber  stopper. 

The  water  bath  is  not  warmed  until  the  evaporat- 
ing dishes  are  filled.  The  saponification  process  begins 

1  Eibner,  Farben  Zeitung,  Nov.  23,  1912. 
65 


66        PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

slowly  and  gradually,  so  that  the  alcoholic  soap  solu- 
tion does  not  crawl  up  to  the  rim  of  the  evaporating 
dishes,  thereby  causing  losses.  The  contents  of  the 
dishes  are  evaporated  to  dryness,  with  constant  stir- 
ring and  breaking  up  of  the  nearly  dry  soaps.  In  this 
way,  the  alcohol  is  completely  removed.  This  whole 
operation  of  saponification  and  evaporation  will  take 
from  1  to  1|  hours.  The  resulting  product  will  be  a 
light  yellow,  agreeable  smelling  soap  powder.  The 
soap  which  first  comes  to  dryness  is  mixed  with  50  c.c. 
of  hot  water  and  dissolved  on  the  boiling  water 
bath.  This  requires  about  5  minutes.  This  soap  solu- 
tion is  added  to  the  soap  which  next  comes  to  dryness, 
and  the  first  evaporating  dish  is  rinsed  out  with  water. 
Finally,  this  solution  is  added  to  the  soap  which  last 
comes  to  dryness.  The  whole  soap  solution  is  cooled 
off  somewhat  and  poured  into  a  1-liter  separatory 
funnel,  graduated  at  180  c.c.  and  340  c.c.  The  volume 
of  the  soap  solution  must  now  amount  to  180  c.c.  and 
must  not  be  any  greater.  The  light  yellow  soap  solu- 
tion, which  is  absolutely  clear  in  a  warm  state,  is  now 
cooled  down  to  the  temperature  of  tap  water,  whereby 
it  becomes  slightly  cloudy.  By  the  addition  of  20 
c.c.  of  five-normal  sulphuric  acid,  the  linseed  fatty 
acids  are  freed,  and  float  on  top  of  the  liquid.  They 
have  an  agreeable,  characteristic  odor  and  are,  in  the 
beginning,  precipitated  in  an  opaque,  white  form. 
After  a  few  seconds,  the  emulsion  disappears.  The 
acids  then  are  plainly  yellow.  The  contents  of  the 
separatory  funnel  are  now  thoroughly  shaken  with 
140  c.c.  of  ether  (second  mark  at  340  c.c.),  during  which 
operation  the  cock  is  opened  at  least  once  to  avoid  ex- 
cessive pressure.  After  5  minutes,  the  aqueous  solu- 
tion is  drawn  off  as  much  as  possible,  the  yellow  ether 


LINSEED  OIL  67 

solution  of  fatty  acids  is  gently  rotated  and  allowed 
to  stand  for  a  minute.  After  this  operation,  a  little 
more  water  will  settle  in  the  lower  part  of  the  separa- 
tory  funnel,  and  is  removed.  After  adding  70  g.  of 
anhydrous  Glauber's  salt,  the  fatty-acid  solution  is 
allowed  to  stand  overnight  in  the  separatory  funnel. 

93.  Procedure.  The  detailed  operation  is  as  fol- 
lows: Saponification  should  not  be  started  until  the 
afternoon.  After  setting  free  the  fatty  acids  with 
sulphuric  acid,  100  c.c.  of  ether  are  first  used  for 
shaking  out  and  allowed  to  stand.  The  aqueous  solu- 
tion is  drawn  off  into  a  second  separatory  funnel,  and 
then  shaken  out  again  with  40  c.c.  of  ether.  The 
combined  ether  solutions  of  fatty  acids  are  then  to  be 
further  treated  as  mentioned  above. 

The  next  forenoon,  the  recovery  of  the  pure  fatty 
acids  is  undertaken.  For  this  purpose,  a  tared  Erlen- 
meyer  flask  of  200  c.c.  capacity  is  used.  The  flask 
is  stopped  with  a  well-pressed,  two-holed  cork  stopper. 
In  one  of  the  holes  is  inserted  a  50-c.c.  dropping  fun- 
nel, which  supports  an  ordinary  small  funnel.  In 
the  other  hole  is  placed  a  glass  tube  of  0.5-cm.  bore, 
bent  at  a  right  angle,  and  this  is  connected  with  a 
Liebig  condenser. 

The  dried  ether  solution  of  fatty  acids  is  now  filtered 
through  a  dry,  folded  filter  (d  =  18.5  cm.)  into  a  150- 
c.c.  Jena  Erlenmeyer  flask  and  from  there  is  poured 
into  the  dropping  funnel.  Then  about  100  c.c.  of 
this  solution  are  run  into  the  200-c.c.  flask  and  the 
water  bath  is  slowly  warmed  to  about  70°  C.  As  the 
ether  is  distilled  off,  more  of  the  solution  is  added, 
drop  by  drop.  The  distilled  ether  is  used  to  extract 
the  Glauber's  salt  in  the  separatory  funnel,  which  has 
absorbed  a  considerable  amount  of  fatty  acids.  This 


68        PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

is  done  six  times,  using  from  100  to  120  c.c.  of  ether 
each  time.  The  fifth  extraction  is,  as  a  rule,  entirely 
colorless.  Finally,  by  means  of  an  ether  wash-bottle, 
the  folded  filter,  the  flask  used  to  receive  the  filtrate, 
the  small  funnel,  and  the  dropping  funnel  are  rinsed 
off,  in  order  to  recover  quantitatively  the  fatty  acids 
adhering  to  them.  After  the  largest  part  of  the  ether 
is  distilled  off,  the  water  bath  is  brought  to  boiling, 
and  a  few  more  cubic  centimeters  of  ether  will  then  be 
distilled  off. 

The  extraction  of  the  Glauber's  salt  and  the  distill- 
ing off  of  the  ether  take  about  1|  hours.  Even  after 
ether  has  ceased  to  distill  over,  the  fatty  acids  still 
contain  some  of  it.  Next,  the  flame  of  the  water 
bath  is  extinguished,  the  Liebig  condenser  and  drop- 
ping funnel  are  removed,  and  a  tight-fitting  stopper, 
with  gas  inlet  and  outlet  tubes,  is  inserted  in  the 
flask.  The  end  of  the  former  tube  is  placed  1  cm. 
above  the  surface  of  the  fatty  acids.  The  outlet 
tube  is  drawn  out  to  a  capillary  to  prevent  the  hydro- 
gen gas,  which  circulates  above  the  fatty  acids,  from 
escaping  too  quickly,  and  to  force  it  to  mix  with  the 
ether  vapors  before  leaving  the  flask.  The  hydrogen 
is  first  purified  by  passing  it  through  an  alkaline  lead 
salt  solution  and  then  through  concentrated  sulphuric 
acid.  The  flask  is  replaced  on  the  water  bath,  which 
is  kept  boiling  vigorously.  In  order  to  drive  off  the 
ether,  two  hours  are  required.  From  four  to  five  gas 
bubbles  per  second  should  pass  through  the  flask. 
Experiments  made  with  carbon  dioxide  instead  of 
hydrogen  give  the  same  results,  but  we  prefer  to  use 
hydrogen.  Next,  the  fatty  acids  are  removed  from 
the  water  bath,  and,  with  a  clean  cloth,  the  hot  flask 
is  wiped  off  on  the  outside  and  inside  around  the  top 


LINSEED   OIL  69 

of  the  neck;  then,  while  warm,  it  is  put  in  a  vacuum 
desiccator.  This  is  evacuated  to  a  high  degree  and 
then  left  standing  for  at  least  4  hours.  By  this  means, 
the  fatty  acids,  as  a  rule,  become  partly  solid.  They 
are  then  weighed  very  quickly  and  put  in  a  vacuum 
as  before.  After  2  hours,  the  flask  is  again  weighed 
as  quickly  as  possible,  the 'weights  having  previously 
been  put  on  the  balance.  Finally,  the  desiccator  with 
flask  is  once  more  evacuated,  and  left  standing  over- 
night. The  next  morning,  the  weight  of  the  flask  is 
checked. 

94.  Preparation  of  the  10  per  cent  ether  solution 
of  fatty  acids.     From  the  9  to  10  g.  of  weighed  lin- 
seed oil  fatty  acids,  a  10  per  cent  ether  solution  is 
now  made.    Forty  cubic  centimeters  of  ether,  dried 
over  calcium  chloride,  are  added  to  the  fatty  acids 
and  carefully  shaken  until  the  latter  are  dissolved. 
This  solution  is  poured  quantitatively  into  an  accu- 
rately  graduated   100-c.c.   glass-stoppered  measuring 
cylinder,  the  graduation  marks  of  which  run  halfway 
around   the   circumference   of   the   cylinder,   whereas 
those  for  every  10  c.c.  run  entirely  around  the  cylin- 
der.   By  means  of  an  ether  wash-bottle,  the  empty 
flask  is  washed  with  20  c.c.  of  ether,  well  shaken,  and 
this  liquid  also  is  poured  into  the  cylinder.     The  flask 
is  then  rinsed  again,  and  care  is  taken  to  wash  off 
whatever  ether  solution  has  run  down  on  the  outside. 
Then  the  cylinder  is  filled  up  nearly  to  the  100-c.c. 
mark  and  shaken.     The  glass  stopper  is  raised  for  a 
moment,  and  after  a  minute  the  cylinder  is  filled  to 
the  mark  and  thoroughly  shaken  once  more.    The 
lower  meniscus  is  read. 

95.  The    Brominizing    process.     By    means    of    a 
standardized  pipette,  marked  at  the  top  and  bottom, 


70         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

20  c.c.  of  the  freshly  shaken  fatty-acid  solution  are 
removed  from  the  graduated  cylinder  and  placed  in 
a  100-c.c.  Jena  Erlenmeyer  flask  with  not  too  narrow  a 
neck.  This  20  c.c.  should  contain  from  1.9  to  2.0  g. 
of  fatty  acids.  A  cork  stopper,  with  a  groove  cut  in 
the  side,  is  placed  in  the  flask,  and  then  the  latter  is 
put  in  a  cooling  mixture  of  a  temperature  not  exceeding 
- 10°  C.  This  mixture  is  prepared  in  a  suitable 
vessel,  such  as  a  water  bath,  by  mixing  finely  broken 
ice  with  the  necessary  quantity  of  salt,  and  thoroughly 
stirring  the  mixture  with  a  strong  glass  rod.  In  win- 
ter, snow  can  be  used.  The  cooling  mixture  must  be 
so  made  that  the  flask  can  be  easily  moved  hi  it.  After 
leaving  the  ether  solution  in  the  cooling  mixture  for  10 
minutes,  it  will  have  the  desired  temperature.  In 
the  meantime,  1  c.c.  of  commercial  bromine  is  placed 
in  the  brominizing  burette.  A  10-c.c.  burette,  or 
even  a  smaller  one,  is  the  most  suitable,  but  the  glass 
cock  must  be  well  ground  in,  and  the  delivery  point 
must  be  fine.  Before  brominizing,  the  flask  contain- 
ing the  fatty-acid  solution  must  be  shaken  slowly  in 
the  cooling  mixture.  Five-tenths  cubic  centimeter  of 
bromine  —  half  of  the  quantity  to  be  used  —  is  added 
in  single  drops,  and  then  the  other  0.5  c.c.  of  bromine, 
in  double  drops,  keeping  the  flask  cold  throughout 
the  operation  by  carefully  shaking  it  in  the  cooling 
mixture.  The  detailed  method  of  procedure  is  as  fol- 
lows: The  cock  of  the  burette  is  slowly  opened,  per- 
mitting a  single  drop  of  bromine  to  run  down  the 
side  of  the  flask,  thereby  preventing  loss  by  spattering. 
The  cock  of  the  burette  is  then  closed,  and  the  flask 
is  shaken  in  the  cooling  mixture.  After  from  12  to  15 
drops  of  bromine  have  been  added  in  this  manner, 
the  hexabromide  of  linolenic  acid  generally  begins  to 


LINSEED   OIL  71 

precipitate  in  the  form  of  a  fine  crystalline  powder, 
which  settles  quickly.  With  every  additional  drop, 
the  precipitate  can  be  plainly  seen  to  increase.  After 
0.5  c.c.  of  bromine  has  been  added  in  single  drops, 
which  should  take  approximately  20  minutes,  the 
other  0.5  c.c.  is  added  in  double  drops  in  exactly  the 
same  manner.  This  will  take  10  minutes,  so  that 
the  entire  brominizing  process  will  consume  30  minutes. 
After  cooling  for  2  minutes  longer,  the  flask  is  again 
shaken  and  then  allowed  to  stand  stoppered  for  2 
hours  in  the  cooling  mixture.  Over  the  precipitate 
can  be  seen  a  reddish  brown  fluid,  a  proof  of  the  excess 
of  bromine  in  the  reaction  mixture.  Quite  frequently 
it  is  observed  that  some  of  the  precipitate  adheres  to 
the  sides  of  the  flask,  due  perhaps  to  the  intense  cool- 
ing. This,  however,  cannot  be  avoided  and  does  not 
influence  the  quantitative  recovery  of  the  precipitated 
hexabromide.  The  time  for  brominizing,  30  minutes, 
must  be  strictly  adhered  to  and  must  not  be  shortened. 
The  added  bromine  disappears  almost  immediately, 
until  an  excess  has  been  added.  During  the  2-hours 
standing,  the  temperature  may  rise  somewhat,  but  in 
order  to  avoid  secondary  reactions  as  far  as  possible, 
it  should  never  exceed  —  5°  C.  In  the  meantime,  the 
washing  ether  is  prepared.  Five  c.c.  of  ether  are  put 
in  each  of  5  test  tubes,  which  are  stoppered  and  set 
in  the  cooling  mixture.  For  filtering,  a  Daniel  filter- 
ing tube  is  used,  which  is  provided  with  an  asbestos 
pad,  made  as  thin  and  uniform  as  possible.  Two 
grams  of  Kahlbaum's  asbestos,  suspended  in  500  c.c. 
of  water,  will  be  sufficient  for  a  series  of  determinations. 
On  top  of  the  asbestos  a  perforated  porcelain  plate  is 
placed,  the  diameter  of  which  must  be  almost  as  large 
as  the  inside  diameter  of  the  filtering  tube.  The  per- 


72         PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

f orated  plate  has  about  20  round  openings,  2  mm.  in 
diameter.  One  liter  of  distilled  water  is  drawn  slowly 
through  the  tube,  and  the  latter,  with  its  cover,  is  then 
dried  for  one  hour  at  110°  C.,  allowed  to  cool  for  an 
hour  in  the  desiccator,  and  then  weighed.  In  weigh- 
ing, the  tube  is  suspended  by  an  aluminum  wire. 
After  the  bromide  precipitate  has  stood  for  2  hours  in 
the  cooling  mixture,  it  is  filtered.  The  tared  filtering 
tube  is  connected  with  a  filtering  flask,  which,  how- 
ever, during  the  whole  filtering  process,  is  not  con- 
nected with  the  pump.  After  making  sure  once  more 
that  the  cooling  mixture  is  at  the  proper  temperature, 
the  operator  removes  the  flask  containing  the  hexa- 
bromide  and  wipes  it  off  with  a  dry  cloth,  without  dis- 
turbing the  precipitate.  With  the  assistance  of  a 
glass  rod,  and  without  disturbing  the  precipitate,  the 
mother-liquor  is  now  carefully  poured  upon  the  filter 
and  allowed  to  drain  through  completely.  In  the 
meantime,  the  precipitate  is  thoroughly  shaken  with 
the  first  5-c.c.  portion  of  washing  ether  and  left  to 
settle  in  the  cooling  mixture.  The  ether  becomes  red- 
dish brown;  the  precipitate  becomes  lighter.  Imme- 
diately after  the  mother-liquor  has  run  through  the 
filter,  the  washing  liquid  in  the  flask  is  poured  upon 
the  filter,  care  being  taken,  however,  to  retain  all  the 
precipitate  in  the  flask.  The  filter  must  never  become 
dry,  as  this  would  cause  a  considerable  delay  in  filtering. 

The  precipitate  is  then  thoroughly  mixed  with  the 
second  5-c.c.  portion  of  ether  and  brought,  as  com- 
pletely as  possible,  upon  the  filter,  immediately  after 
the  first  portion  of  washing  ether  has  drained  through. 
The  precipitate  settles  instantly,  and  above  it  is  a 
yellow  solution  which  filters  easily. 

The  flask  is  then  cleaned  with  a  feather,  using  the 


LINSEED   OIL  73 

third  5-c.c.  portion  of  ether.  Next,  the  precipitate 
still  remaining  in  the  flask  is  stirred  up  and  brought 
upon  the  filter  immediately  after  the  preceding  wash- 
ing liquid  has  drained  through.  Then,  the  precipitate 
on  the  filter  is  stirred  with  a  glass  rod  and  is  thus 
freed  as  much  as  possible  from  the  mother-liquor. 
At  this  point,  the  washing  ether,  filtering  through, 
still  has  a  yellowish  color,  but  the  precipitate  is  almost 
white.  The  flask  is  again  cleansed  with  the  feather, 
using  the  fourth  portion  of  ether.  The  latter,  which 
is  then  colorless  and  contains  only  a  trace  of  precipi- 
tate, is  also  poured  upon  the  filter  in  such  a  way  as 
to  rinse  the  rim  of  the  filtering  tube,  up  to  which 
some  of  the  mother-liquor  has  crawled  during  filtra- 
tion. The  precipitate  on  the  filter  is  once  more  stirred 
up  with  the  glass  rod.  The  ether  filtering  through  is 
now,  hi  most  cases,  very  faintly  yellowish  or  colorless. 
Then  the  last  5-c.c.  portion  of  ether  is  used  to  rinse 
the  flask  once  more.  The  glass  rod  is  now  cleaned 
with  the  feather,  and  the  entire  contents  of  the  flask 
are  brought  upon  the  filter  and  allowed  to  run 
through.  Then,  with  the  filtering  tube  half  covered, 
the  filtering  flask  is  connected  with  the  suction  pump, 
and  the  latter  is  worked  strongly  for  one  minute. 
The  hexabromide  shrinks  to  a  very  nice  white  mass. 
Occasionally,  cracks  occur  in  the  precipitate.  A  small 
quantity  of  a  slightly  yellowish  fluid  is  drawn  from  the 
bromide  by  the  suction  process,  and  the  lower  part  of 
the  filtering  tube  often  becomes  somewhat  clouded 
with  a  small  amount  of  residue  left  after  the  washing 
ether  has  evaporated.  The  filtering  tube  is  now  re- 
moved from  the  filtering  flask,  wiped  off  outside,  and 
heated  in  a  drying  oven  for  2  hours  at  from  80  to 
85°  C.  Then  it  is  allowed  to  cool  for  1  hour  in  the 


74         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

desiccator  and  is  weighed.  It  has  often  been  observed 
that  a  hexabromide,  which  would  be  snow-white  in 
color  if  dried  at  80°  C.,  becomes  gray  on  the  surface 
if  dried  at  100°  C.  During  filtration,  especially  dur- 
ing the  first  half  of  it,  the  precipitate  must  never 
become  dry.  Should  this  happen  before  the  hexabro- 
mide is  thoroughly  pure,  it  can  hardly  be  washed  out 
completely,  as  sticky  substances,  bromides  of  vari- 
ous compositions,  which,  once  dried,  are  difficult  to 
dissolve  in  ether,  adhere  to  the  original  precipitate. 
Before  drying,  the  precipitate  must  be  white,  inside 
and  out.  If  it  shows  a  yellow  color  anywhere,  it  will 
partially  melt  during  the  drying  process  and  become 
gray  on  the  surface.  The  weight  will  then  be  some- 
what too  high.  The  filtering,  as  a.  rule,  takes  from 
10  to  15  minutes  and  should  not,  at  all  events,  exceed 
25  minutes.  The  condition  of  the  asbestos  greatly 
influences  the  period  of  filtration.  The  hexabromide 
number  is  obtained  by  calculating  the  weight  of  hexa- 
bromide per  100  g.  of  fatty  acids. 

96.  Modifications.  Thompson 1  has  adopted  the 
following  modifications.  The  pure  fatty  acids  were 
poured  into  small  vials  holding  approximately  2.0  g. 
when  full  and  tightly  corked.  In  this  way,  the 
fatty  acids  can  be  preserved  for  a  considerable  period 
without  appreciable  change.  To  make  the  test,  the  con- 
tents of  one  of  the  vials  were  poured  into  a  weighed 
Erlenmeyer  flask  of  100  c.c.  capacity,  flask  and  con- 
tents reweighed,  and  the  fatty  acids  dissolved  in  20 
c.c.  of  ether.  1.9  to  2.0  was  found  to  be  a  convenient 
quantity  to  work  with. 

After  the  flasks  had  stood  in  the  freezing  mixture  at 
— 10°  C.  for  two  hours,  the  filtering  and  washing  were 
1  Am.  Soc.  Test.  Mat.,  Vol.  XV,  page  233 


LINSEED   OIL  75 

carried  out  as  follows:  A  small  wash-bottle  containing 
ether  was  placed  in  a  separate  freezing  bath  and  the 
contents  cooled  to  -  10°  C.  The  tip  of  the  bottle 
was  made  to  deliver  a  very  fine  stream.  The  time 
required  to  deliver  the  proper  amount  of  wash  ether 
was  determined  by  experiment  and  can  be  judged  very 
closely. 

The  flask  was  removed  from  the  freezing  bath  and 
the  mother-liquor  carefully  decanted.  The  precipi- 
tate was  then  washed  down  with  a  fine  stream  of 
ether,  using  about  5  c.c.,  and  the  precipitate  and 
wash  ether  shaken  thoroughly  and  allowed  to  settle 
out  in  the  freezing  bath.  This  washing  by  decanta- 
tion  was  repeated  three  times.  The  precipitate  was 
then  transferred  to  a  Gooch  crucible,  and  the  flask 
was  washed  out  with  about  5  c.c.  of  ether.  It  is  sel- 
dom that  any  precipitate  will  be  found  adhering  to 
the  flask,  but  if  such  is  the  case,  it  can  be  removed 
with  an  ordinary  rubber  policeman.  The  precipitate 
on  the  Gooch  crucible  was  allowed  to  drain,  using  a 
gentle  suction  if  necessary;  but  care  should  be  taken 
to  prevent  the  precipitate  from  becoming  dry.  Wash- 
ing was  continued  on  the  Gooch  crucible,  stirring  up 
the  precipitate  each  time  with  a  fine  stream  of  ether, 
and  allowing  it  to  drain  almost  dry,  until  the  wash 
ether  appeared  colorless.  Strong  suction  was  then 
applied  and  the  precipitate  freed  from  the  liquid. 
The  Gooch  crucible  was  removed  and  placed  in  a  steam 
bath  which  was  held  at  80°  C.  and  dried  for  one  hour. 
The  liquid  in  the  filtering  flask  will  be  found  to  be 
about  50  c.c.,  and  should  not  exceed  this  amount. 

In  following  out  this  method  results  have  been 
obtained  which  agree  closely  with  those  reported  by 
Eibner. 


76         PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

TABLE  XV 
97.  Percentage  of  hexabromides 1 

N°-  Source  HexabSdes 

1 FromN.  A.  Seed  48.90 

2 "      "    "      "  48.57 

3 "      "    "      "  51.88 

4 "     S.  A.  Seed  48.59 

5 "     Bombay  Seed  50. 87 

98.  Boiled  linseed  oil.  The  American  Society  for 
Testing  Materials  adopted  in  1915  the  following  stan- 
dard specifications  for  boiled  linseed  oil  from  North 
American  seed. 

Maximum          Minimum 

Specific  gravity  at  1^A°  C 0.945  0.937 

15.5 


Acid  number 

Saponification  number.  . 
Unsaponifiable  matter . . 
Refractive  index  at  25°  C.  .  .  . 
Iodine  number  (Hanus) , 


8 

195       189 
1.5 
1.484     1.479 

178 

0.7  0.2 

0.03 


Ash,  per  cent. 
Manganese,  per  cent. 

Calcium,  per  cent 0.3 

Lead,  per  cent 0.1 

99.  Effect  of  hydrolysis  on  the  acid  number.2  Since 
the  metallic  linoleates  and  resinates  are  so  easily 
hydrolyzed,  it  is  apparent  that  their  presence  in  the 
dissolved  state  would  cause  an  oil  or  varnish  to  show 
an  acid  value,  which  would  include  the  amount  of 
alkali  necessary  to  hydrolyze  the  soaps  present  as 
driers,  as  well  as  that  required  to  neutralize  the  free 
fatty  acids. 

Lead,  manganese,  cobalt,  and  zinc  linoleates  hydro- 
lyze completely  during  titration.  Calcium  linoleate 

1  Thompson,  Proceedings  A.  S.  T.  M.,  Vol.  XIII,  page  378  (1913). 

2  Ware  &  Christman,  J.  Ind.  and  Eng.  Chem.,  Vol.  VIII,  page  996 
(1916). 


LINSEED   OIL  77 

hydrolyzes  to  the  extent  of  50  per  cent.     The  rosin 
salts  of  the  same  metals  hydrolyze  as  follows: 


Lead  salt 

Calculated 
Acid  Value 
Assuming 
Complete  Hy- 
drolysis 

139  0 

Apparent 
Acid 
Value 

113 

Per  Cent 
Hydrolyzed 

81.3 

Manganese  salt  .  .  . 
Cobalt  salt  

171.2 
170.3 

168 
160 

98.3 
94.0 

Calcium  salt  
Zinc  salt  

175.3 

168.7 

86 
149 

49.1 

88.3 

To  arrive  at  the  true  acid  value  of  boiled  oil,  enamel 
liquid,  or  varnish,  it  is  therefore  necessary  to  deduct 
from  the  total  amount  of  alkali  used  the  amount 
required  to  hydrolyze  the  metallic  soaps  present. 

100.  Grinding  oils.     For  grinding  white  lead  and 
combination  paste  whites,  specially  prepared  linseed 
oils  are  used,  which  have  been  largely  freed  from  the 
coloring   principles   that   would   otherwise   stain   the 
paint  yellow.    These  grinding  oils  are  made  to  meet 
the  various  requirements  of  the  paint  grinder  as  to 
acid   number,    some   having   low   acid   values   while 
others  have  acid   numbers   of   from  12  to  16.    The 
determination  of  the  acid  value  is  therefore  of  prime 
importance.     The  other  constants  will  be  found  to 
correspond  to  those  of  raw  linseed  oil. 

101.  Bodied    linseed    oils.    These    oils    may    be 
divided  into  two  classes,  viz.: 

Blown  oils,  prepared  by  blowing  air  through  a 
moderately  heated  oil,  which  has  been  previously 
freed  from  foots,  until  the  desired  consistency  has 
been  obtained.  These  oils  are  characterized  by  a  low 
acid  number  of  about  6  to  7,  very  heavy  body,  a  low 
iodine  number  and  a  tendency  to  become  insoluble  on 
standing  after  having  been  largely  diluted  with  naphtha. 

Heat  bodied  oils,  prepared  by  heating  a  linseed  oil 


78         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

that  has  been  freed  from  foots  and  so  treated  that  it 
becomes  nearly  water-white  when  heated  to  about 
600°  F.  The  heating  is  continued  at  this  tempera- 
ture until  the  desired  body  has  been  obtained.  Such 
oils  have  high  acid  values,  varying  from  15  to  30  or 
even  higher  according  to  the  amount  of  heat  they 
have  received.  The  iodine  value  decreases  rapidly  as 
the  body  increases,  and  with  very  heavy  oils  may  be 
less  than  100.  Such  oils  are  used  extensively  in  enamel 
liquids,  certain  varnishes  and  in  reducing  oils. 


CHAPTER  VIII 

TUNG  OIL  (CHINESE  WOOD  OIL) 

102.  Valuation.  The  paint  manufacturer  is  en- 
abled to  control  the  purity  of  his  linseed  oil  by  pur- 
chasing direct  from  the  crusher;  with  tung  oil  he 
has  no  such  assurance,  as  the  oil  will  have  passed 
through  several  hands  before  it  reaches  him.  As  this 
oil  is  frequently  adulterated  and  as  it  requires  only  a 
small  percentage  of  adulteration  to  seriously  impair 
its  value  in  varnishes,  it  is  necessary  that  each  ship- 
ment be  carefully  tested. 

Because  of  the  fact  that  a  very  small  percentage  of 
adulteration  seriously  affects  the  working  qualities  of 
tung  oil,  the  ordinary  chemical  constants  cannot  be 
relied  upon  in  determining  its  purity  and  suitability 
for  use.  Neither  can  the  so-called  heat  or  "gel" 
tests  that  are  in  common  use  be  relied  upon  to  detect 
adulteration.  The  author  has  tested  numerous  ship- 
ments that  have  been  passed  as  pure  by  skilled  opera- 
tors using  these  standard  tests,  and  he  has  found  these 
shipments  adulterated  and  unsuitable  for  use.  The 
extremely  unsatisfactory  condition  of  the  tung  oil 
market  during  the  winter  of  1918-19,  when  large 
quantities  of  impure  oil,  which  had  nevertheless  been 
certified  as  of  satisfactory  purity  by  various  labora- 
tories, were  passing  from  one  dealer  to  another  in 
an  effort  to  unload,  thus  causing  a  badly  demoral- 
ized market,  is  ample  confirmation  of  the  above 
statements. 

79 


80         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

103.  Anomalous     dispersion     of     tung     oil.      The 
method,   developed   in   the  author's   laboratory,   has 
been  found  very  satisfactory  and  has  been  used  by 
him  for  valuing  importations  of  tung  oil  for  six  suc- 
cessive years.    This  method  is  based  on  the  phenome- 
non of  the  anomalous  dispersion  —  inversion  of  the 
spectrum  —  exhibited  by  tung  oil  under  certain  con- 
ditions and  its  return  to  the  normal  position  by  the 
addition  of  a  known  percentage  of  another  vegetable 
oil.     Of  all  the  oils  examined  by  the  author 1  tung  oil, 
alone,  exhibits  a  spectrum  with  the  green  at  the  top 
and  red  at  the  bottom,  the  other  oils  showing  the 
characteristic  spectrum,  the  red  at  the  top  and  the 
green  at  the  bottom.     The  addition  of  15  to  25  per 
cent,  depending  upon  the  natural  purity  of  the  tung 
oil,  of  another  vegetable  oil,  e.g.,  linseed,  causes  the 
spectrum  to  resume  its  normal  position.    The  per- 
centage of  such  added  oil  required  to  obtain  a  normal 
spectrum  affords  a  direct  numerical  measure  of  the 
purity  of  the  tung  oil  and  is  known  as  its  turning 
point  value. 

104.  Constitution   of  tung   oil.     Tung  oil  is   com- 
posed essentially  of  the  glycerides  of  elaeomargaric  and 
oleic  acids.    The  glyceride  of  oleic  acid  exhibits  nor- 
mal dispersion  only  and  in  admixture  with  the  elaeo- 
margaric glyceride  acts  solely  as  a  diluent.    Therefore 
the  "  turning  point,"  i.e.,  the  point  when  the  disper-* 
sion  ceases  to  be  anomalous  and  becomes  normal, 
depends  on  the  amount  of  olein  present  in  the  oil. 

Ware  &  Schumann,2  from  the  results  obtained  by 
the  potassium  soap  and  light  break  methods,  concluded 
that  the  percentage  of  elaeomargaric  glyceride  nor- 

1  Drugs,  Oils  and  Paints,  Vol.  XXXI,  No.  9,  page  327. 

2  J.  Ind.  and  Eng.  Chem.,  6  (1914),  806,  8. 


TUNG  OIL   (CHINESE  WOOD  OIL)  81 

mally  present  in  tung  oil  varies  from  90  to  94  per 
cent.  One  of  the  samples  they  reported  on  as  con- 
taining 10  per  cent  olein  was  found  by  the  author  to 
have  a  turning  point  of  15.5,  indicating  that  a  tung 
oil  composed  of  elaeomargaric  glyceride  only,  would 
have  a  turning  point  of  25.5.  That  this  assumption  is 
approximately  correct  is  evidenced  by  the  fact  that 
the  author  examined  a  sample  of  tung  oil  obtained 
direct  from  China  having  a  turning  point  of  24.9  and 
a  domestic  sample  obtained  from  nuts  grown  in  Florida 
having  a  turning  point  of  25.  Both  samples  had  only 
a  fraction  of  1  per  cent  of  oleic  acid  and  its  glyceride, 
olein. 

105.  Procedure.  The  method  depends  on  the  inver- 
sion of  the  spectrum,  using  a  Pulfrich  refractometer. 
The  essential  features  of  the  apparatus  are:  a  90- 
degree  Pulfrich  prism  (index  of  refraction  1.62)  carry- 
ing a  cell  so  mounted  that  the  upper  surface  of  the 
prism  is  above  the  level  of  the  joining  of  the  cell  and 
prism;  a  powerful  tungsten  light  as  the  source  of  the 
illumination;  a  slitted  screen  to  eliminate  the  excess  rays, 
and  a  telescope  for  observing  the  spectrum  produced. 

A  weighed  quantity,  about  15  per  cent,  of  pure 
linseed  oil  free  from  foots  and  moisture  is  added  to 
the  sample  of  tung  oil  to  be  tested,  the  mixture  heated 
gently  to  not  exceed  100°  C.,  thoroughly  stirred  and 
cooled  to  25°  C.  at  which  temperature  the  spectrum 
of  the  mixture  is  observed.  Further  weighed  quan- 
tities of  linseed  may  have  to  be  added  to  cause  the 
spectrum  to  resume  its  normal  position,  showing  a 
distinct  very  narrow  band  of  red  along  the  upper 
edge  of  the  spectrum.  This  being  the  most  marked 
change  and  the  one  most  readily  observed,  the  descrip- 
tive term,  "  turning  point,"  has  been  applied  to  it. 


82          PAINT   VEHICLES,   JAPANS  AND   VARNISHES 

Further  additions  of  linseed  oil  merely  increase  the 
distinctness  of  the  red  and  cause  the  gradual  appear- 
ance of  the  green,  until  finally  the  entire  spectrum 
has  been  completely  reversed  to  its  normal  position. 

106.  Variation  in  the  composition  of  tung  oil.     The 
natural  composition  of  tung  oil  is  subject  to  variation 
from  year  to  year,  due  presumably  to  climatic  condi- 
tions.    In  no  instance,  however,  has  the  author  found 
a  well  authenticated  shipment  of  tung  oil  of  com- 
mercial purity  to  contain  more  than  10  per  cent  olein 
or  have  a  turning  point  value  of  less  than  15.5  at  25° 
C.     Commercial  shipments  have  been  examined  hav- 
ing a  turning  point  value  of  22,  equivalent  to  approxi- 
mately 3  per  cent  olein. 

107.  Normal    purity.     In    judging    the    purity    of 
tung  oil,  it  is  therefore  necessary,   first  to  establish 
the  normal  purity  of  the  oil  crop  of  the  current  year, 
taking  into  consideration  that   several  months  elapse 
from  the  time  the  nuts  are  harvested  until  the  oil  is 
received  in  this  country. 

Commercially  acceptable  shipments  of  tung  oil  for 
1913,  1914,  and  1915  gave  a  very  uniform  turning 
point  value  of  15.5  at  25°  C.;  in  1916  this  value  varied 
from  19  to  21,  and  hi  1917  from  20  to  22,  while  in 
1918  it  dropped  to  16  from  18.  Tung  oil  of  low  acid 
number  and  having  a  turning  point  value  of  15.5  has 
been  found  in  actual  practice  to  be  satisfactory  in  all 
respects. 

If  the  normal  turning  point  value  for  the  current 
year  should  be  found  to  be  15.5  and  a  certain  ship- 
ment gave  a  value  of  10,  the  oil  would  be  considered 
adulterated  to  the  extent  of  5.5  per  cent. 

108.  Acid  value.     In  actual  practice  the  author  has 
found  that  the  higher  the  acid  value,  the  turning  point 


TUNG  OIL   (CHINESE  WOOD  OIL)  83 

value  remaining  constant,  the  slower  will  be  the  oil 
to  acquire  its  "body"  in  the  varnish  kettle.  Know- 
ing both  the  turning  point  values  and  the  acid  num- 
ber, the  behavior  in  the  varnish  kettle  of  one  tung  oil 
compared  with  another  can  be  very  definitely  deter- 
mined, and  therefore  this  method  of  examination  is  of 
direct  value  to  the  varnish  maker  in  governing  the 
treatment  that  the  tung  oil  will  receive. 

The  following  table l  gives  the  results  from  tung 
oils  obtained  direct  from  the  primary  Chinese  mer- 
chants in  the  local  districts  where  the  1916  oil  crop 
was  produced. 

TABLE  XVI 
109.   Imported  tung  oUs. 

Number  Acid  Value 

1 7.3  23.6 

2 2.5  20.5 

3 t 3.7  23.9 

4 7.6  22.3 

5 1.4  24.9 

6 6.6  22.5 

Average 23. 0 

110.  Climatic  influences.  The  influence  of  cli- 
matic conditions  as  affecting  the  composition  of  tung 
oil  is  clearly  shown  in  the  accompanying  table.2  These 
domestic  produced  oils  were  obtained  direct  from  the 
1916  crop  of  nuts  by  the  author,  the  meats  being 
heated  to  80°  C.  and  subjected  to  hydraulic  pressure. 

1  Drugs,  Oils  and  Paints,  Jan.  1917. 

2  Drugs,  Oils  and  Paints,  May,  1917. 


84         PAINT  VEHICLES,   JAPANS  AND   VARNISHES 


TABLE  XVII 


111.  Domestic  tung  oils. 


No. 

Source 

Color 

Specific 
Gravity 
15.  5°  C. 

T.  P.  Value 
25°  C. 

Acid 
Value 

t 

Georgia  Exp.  Station  

Very  Pale 

.9408 

23.4 

0.49 

fl 

Fairhope,  Alabama.-  

fi 

9402 

23  0 

0  37 

3 

Ala.  Board  of  Horticulture 

« 

.9383 

23.0 

0.79 

4 

Tallahassee,  Florida  

" 

.9402 

25.0 

0.60 

5 

Univ.  of  California  

" 

.9368 

9.0 

0.45 

6 

Riverside,  California  

.9365 

8.0 

0.50 

Oils  numbers  5  and  6  would  be  unsatisfactory  for 
commercial  usage  and  when  examined  by  the  method 
developed  by  the  author,  as  well  as  by  the  procedure 
defined  by  the  American  Society  for  Testing  Materials 
and  also  by  practical  test,  would  be  considered  as 
heavily  adulterated. 

Standard  Specifications  for  Purity  of  Raw  Tung 

Oil  Adopted  by  the  American  Society  for 

Testing  Materials  (1916) 


112.   Properties.     Raw   tung 
the  following  requirements: 

Specific  Gravity  at  J^i|! 


oil   shall   conform   to 


Maximum  Minimum 

....  0.943  0.939 

Acid  Number 6 

Saponification  Number 195  190 

TJnsaponifiable  Matter,  per  cent 0. 75 

Refractive  Index  at  25°  C 1.520  1.515 

Iodine  Number  (Hiibl,  18  hours) 165 

Heating  Test  (Browne's  Method),  minutes        12 
Iodine  Jelly  Test,  minutes 4 

113.  Specific  gravity.  Use  a  pycnometer  accu- 
rately standardized  and  having  a  capacity  of  at  least 
25  c.c.,  or  any  other  equally  accurate  method,  making 
the  test  at  15.5°  C.,  water  being  1  at  15.5°  C. 


TUNG   OIL   (CHINESE  WOOD  OIL)  85 

114.  Acid   number.     Weigh   10  g.  of  oil  in  a  200- 
c.c.  Erlenmeyer  flask,  add  50  c.c.  of  neutral  alcohol, 
connect  with  a  reflux  air  condenser  (or  place  small 
funnel  in  neck  of  flask),  and  heat  on  a  steam  bath  for 
|  hour.     Remove   from   the  bath,  cool,  add  phenol- 
phthalein,  and  titrate  the  free  acid  with  N/5  sodium 
hydroxide.     Calculate  as  the  acid  number  (milligrams 
of  potassium  hydroxide  to  1  g.  oil). 

115.  Saponification  number.     Weigh  from  2  to  3  g. 
of  oil  in  a  200-c.c.  Erlenmeyer  flask,  add  30  c.c.  of 
N/2  alcoholic  solution  of  potassium  hydroxide,  con- 
nect with  a  reflux  condenser,  heat  on  a  steam  bath 
for  1  hour,  then  titrate  with  N/2  sulphuric  acid,  using 
phenolphthalein  as  indicator.    Always  run  two  blanks 
with  the  alcoholic  potash.     From  the  difference  be- 
tween the  number  of   cubic  centimeters  of  acid  re- 
quired by  the  blanks  and  the  determinations,  calculate 
the  saponification  number   (milligrams   of  potassium 
hydroxide  to  1  g.  of  oil). 

116.  Unsaponifiable   matter.     To  25  g.  of  oil  add 
,15  c.c.   of  an  aqueous  solution  of  KOH   (200  g.  of 
KOH   dissolved  in  water  and  made  up  to  300  c.c.) 
and  35  c.c.  of  95  per  cent  alcohol.     Connect  with  a 
reflux   condenser   and  heat  on  the  water  bath  for  1 
hour  with  occasional  shaking.     Transfer  to  a  separa- 
tory  funnel  containing  a  little  water  and  wash  out 
flask  with  water,  using  in  all  125  c.c.    Cool,  add  200 
c.c.  of  ether  and  shake  vigorously  for  1  minute.     In  a 
few  minutes  the  ether  solution  will  separate  perfectly 
clear.     Draw  off  the  soap  solution  into  another  sepa- 
ratory  funnel.     Shake  the  soap  solution  with   three 
100-c.c.  portions  of  ether.     Unite  all  the  ether  por- 
tions and  wash  with  three  30-c.c.  portions  of  water. 
Filter  the  ether  solution  (small  portions  at  a  time)  into 


86         PAINT   VEHICLES,   JAPANS  AND   VARNISHES 

a  tared  flask,  distill  off  the  ether  and  dry  flask  and 
contents  to  constant  weight  at  95  to  100°  C.  in  a 
steam  oven.  Report  the  percentage  of  unsaponifiable 
matter. 

117.  Refractive  index.     Use  a  properly  standardized 
Abbe  refractometer  at  25°  C.,  or  any  other  equally  ac- 
curate instrument. 

118.  Iodine  Number  (Hiibl).     Place  a  small  quan- 
tity of  oil  into  a  small  weighing  bottle  or  beaker. 
Weigh  carefully.     Transfer  by  dropping  from  0.2  to 
0.3   g.   into   a   500-c.c.   bottle   having   a   well-ground 
stopper,   or  a  specially  flanged  neck,  iodine-test   Er- 
lenmeyer  flask.     Reweigh  the  weighing  bottle  or  beaker 
to  determine  the  amount  of  oil  used  in  the  test.     Then 
dissolve  the  oil  in  10  c.c.  of  chloroform  and  add  an 
amount  of  Hiibl  solution  containing  twice  the  amount 
of  iodine  that  will  be  absorbed  by  the  oil.     Stopper 
the  flask,  shake  well,  and  place  in  a  dark  closet  for  18 
hours.     Add  20  c.c.  of  a  10  per  cent  solution  of  potas- 
sium iodide  and  100  c.c.  of  distilled  water.     Titrate 
with  N/10  sodium  thiosulphate,  using   starch  as  an 
indicator.     Blank    tests    must    be    made.     From    the 
difference  between  the  amounts  of  sodium  thiosulphate 
required  by  the  blanks  and  the  determination,  calcu- 
late the  iodine  number  (centigrams  of  iodine  to  1  g. 
of  oil). 

On  account  of  the  fact  that  Hiibl  solution  after 
preparation  is  apt  to  deteriorate  in  strength,  it  is  con- 
sidered advisable  to  have  prepared  the  two  component 
parts  of  Hiibl  solution,  namely,  a  solution  of  mercuric 
chloride  in  alcohol  and  a  solution  of  iodine  in  alcohol, 
of  the  proper  strength,  as  outlined  in  text-books. 
The  proper  amounts  of  these  solutions  may  be  mixed 
on  the  day  of  use. 


TUNG  OIL   (CHINESE  WOOD  OIL)  87 

119.  Heating  test  (Browne's  method).     Test  tubes 
for  containing  the  oil  should  be  16  cm.  by  15  mm., 
with  a  mark  near  the  bottom  to  indicate  5  c.c.,  and 
closed  by  a  cork  so  perforated  that  a  glass  rod  3  mm. 
in  diameter  can  move  freely. 

Fill  a  copper  beaker  (height,  12  cm.;  internal  diam- 
eter, 6  cm.)  with  cotton-seed  oil  to  a  height  of  7.5 
cm.  Place  a  thermometer  so  as  to  be  1.5  cm.  from 
the  bottom  of  the  bath. 

Use  a  nitrogen-filled  immersed-stem  chemical  ther- 
mometer, engraved  stem;  total  length  4  to  4|  in.; 
graduated  from  210  to  310°  C.  in  2°  intervals;  the 
length  between  210  and  310°  C.  not  less  than  2|  in. 
If  preferred,  use  emergent-stem  thermometer  30  cm. 
long,  with  graduations  from  100  to  400°  C.,  making 
correction  for  emergent  stem  according  to  the  method 
outlined  in  Stem  Correction  Sheet  No.  44  of  the  U.  S. 
Bureau  of  Standards. 

120.  Procedure.     When    the   bath    temperature   is 
293°  C.  (560°  F.)  and  very  slowly  rising  at  this  point, 
place  the  tube  containing  5  c.c.  of  the  oil  to  be  tested 
so  that  its  bottom  is  level  with  the  lowest  part  of 
the  bulb  of  the  thermometer.     Note  the  tune,  remove 
the  source  of  heat  for  about  45  seconds,  and  then  re- 
apply.     Before  2  minutes  have  elapsed  the  tempera- 
ture of  the  bath  will  have  fallen  to  282°  C.  (540°  F.), 
at  which  point  it  should  be  kept  as  steady  as  possible. 
When  the  tung  oil  has  been  hi  the  bath  about  9 
minutes,  raise  the  glass  rod  at  intervals  of  |  minute,  and 
when  the  rod  is  firmly  set  note  the  tune.  As  setting  or 
jellying  takes  place  within  a  few  seconds  of  fluidity,  a 
good  end  determination  is  afforded.   Remove  the  speci- 
men at  once,  heat  the  bath  again  to  293°  C.,  and  repeat 
the  experiment  with  another  portion  of  the  sample. 


88         PAINT   VEHICLES,   JAPANS  AND  VARNISHES 


No  stirrer  is  used  in  the  bath.  A  screen  around 
the  bath  enables  the  temperature  to  be  more  easily 
reached.  When  the  cotton-seed  oil  has  become  tarry 
and  viscid,  it  should  be  renewed;  otherwise  heating 
may  be  irregular. 

121.  Iodine  jelly  test.  In  a  wide-necked  200-c.c. 
Erlenmeyer  flask,  place  2.5  g.  (weight  correct  to  1 
mg.)  of  the  oil.  Add  10  c.c.  of  chloro- 
form from  a  pipette  and  stopper  the 
flask  immediately.  Carefully  insert  a 
small  glass  vial  into  the  flask  so  that 
the  vial  stands  upright.  Into  the  vial 
from  a  pipette  run  10  c.c.  of  a  solution 
of  iodine  in  chloroform,  containing 
0.035  to  0.036  g.  of  iodine  per  cubic 
centimeter.  Place  the  flask  in  a  bath 
containing  water  at  25  to  26°  C.  and 
allow  it  to  stand  there  for  a  few  minutes. 
Keep  the  flask  stoppered,  except  when 
it  is  necessary  to  remove  it  to  insert 
the  vial  and  to  add  the  iodine  solution. 
Tilt  and  rotate  the  flask  so  that  the  vial 
is  upset  and  the  contents  of  the  flask 
are  thoroughly  mixed,  at  the  same  time 
starting  a  stop  watch.  Keep  the  flask 
in  the  bath  at  25°  to  26°  C.  and  at  the 
end  of  every  quarter  minute,  tilt  the  flask  towards  a 
horizontal  position.  Note  the  time  required  for  the  for- 
mation of  a  jelly  that  does  not  flow,  but  sticks  to  the 
bottom  of  the  flask  or  slides  as  a  mass.  Record  time 
in  minutes  and  quarters  thereof.  Pure  tung  oil 
should  require  2f  to  3j  minutes  for  the  formation  of 
the  jelly.  If  the  temperature  of  the  laboratory  is 
more  than  2  or  3°  C.  above  or  below  25°  C.,  place 


FIG.  5 


TUNG   OIL   (CHINESE  WOOD  OIL)  89 

the  flask  containing  the  iodine  solution  in  the  bath 
and  allow  it  to  remain  there  for  several  minutes  before 
pipetting  out  the  10  c.c.  for  the  test.  The  arrange- 
ment of  the  apparatus  is  shown  in  Fig.  5.  The  chloro- 
form used  to  dissolve  the  oil  and  to  prepare  the  iodine 
solution  shall  conform  to  the  requirements  of  the 
United  States  Pharmacopoeia  and  shall  have  specific 
gravity  at  25°/25°  C.  of  not  more  than  1.481  and  not 
less  than  1.480.  The  proper  density  can  be  obtained 
by  washing  with  water  if  the  specific  gravity  is  too 
low,  or  by  adding  95  per  cent  ethyl  alcohol  if  too  high. 

122.  Preparation  of  iodine  solution.     A  convenient 
procedure  for  preparing  the  iodine  solution  is  as  fol- 
lows:  Treat  an  excess  of  iodine  with  warm  chloroform 
and  after  shaking  for  a  few  minutes,  cool  the  contents 
to  about  20°  C.  and  filter  through  glass  wool.     Pipette 
10  c.c.  of  the  solution  into  a  flask  containing  10  c.c. 
of  10  per  cent  potassium-iodide  solution  and  titrate 
with  0.1   normal  sodium-thiosulphate  solution.     Cal- 
culate the  iodine  content  and  dilute  with  chloroform 
so  as  to  obtain  an  iodine  content  of  0.035  to  0.036  g. 
per    c.c.    After    dilution,    titrate    again    against    the 
thiosulphate  to  be  sure  that  the  solution  is  of  required 
strength. 

All  the  details  of  the  above  method  shall  be  followed 
exactly. 

123.  Regulations  of  New  York  Produce  Exchange 
regarding  purity  of  tung  oil.1     "Pure  China  wood  oil 
shall    answer    the    accepted    chemical    requirements. 
The  oil  shall  stand  the  heat  test  herewith  subjoined." 

Heat  test.  One  hundred  grams  of  the  oil  are  heated 
in  an  open  metal  pan,  6  inches  in  diameter,  as  rapidly 
as  possible,  to  a  temperature  of  540  degrees  Fahrenheit. 

1  Rules  New  York  Produce  Exchange  (effective  July  1,  1918). 


90         PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

The  time  required  to  heat  the  oil  from  room  tem- 
perature to  540  degrees  should  be,  as  nearly  as  pos- 
sible, the  same  each  time,  four  minutes  being  usually 
sufficient  with  gas  burners.  Hold  the  oil  at  or  as  near 
to  540  degrees  as  possible,  stirring  until  it  begins  to 
solidify.  Note  the  time  required  after  the  oil  reaches 
540  degrees,  and  until  it  begins  to  solidify.  This 
should  not  exceed  *I\  minutes  for  any  commercially 
prime  wood  oil.  When  the  oil  has  solidified  in  the 
pan,  turn  it  out  while  still  hot,  and  cut  with  a  knife. 
Commercially  prime  wood  oil  gives  a  product  that  is 
pale,  firm,  and  cuts  under  the  knife  like  dry  bread, 
not  sticking.  If  the  oil  requires  more  than  7|  minutes 
after  reaching  540  degrees  until  beginning  to  solidify, 
or  if  the  product  is  dark,  soft,  or  sticky,  the  oil  may 
be  rejected. 


CHAPTER  IX 

MISCELLANEOUS  PAINT  AND  VARNISH   OILS 

124.  Soya  oil.     Due  to  the  increasing  demand  for 
linseed  oil  and  the  scarcity  of  this  article,  paint  and 
varnish  manufacturers  are  being  forced  to  seek  a  sub- 
stitute for  this  important  material.     Of  the  oils  com- 
mercially obtainable  in  sufficient  quantities  to  meet 
the  needs  of  these  industries,  soya  oil  has  been  found 
the  most  satisfactory  and  adaptable. 

125.  Uses.     Soya  oil  has  been  used  to  a  consider- 
able extent  without  admixture  with  other  oils  in  oil 
colors,  paste  and  semi-paste  paints.     Generally  it  is 
used  in  conjunction  with  linseed  oil  with  the  proper 
driers  and  is  to  a  limited  extent  a  component  of  var- 
nishes and  enamel  liquids.     From  the  following  table 
(XVIII)  it  is  evident  that  the  iodine  value  of  soya  oil 
is  the  only  chemical  constant  that  markedly  differen- 
tiates it  from  linseed  oil.    The  average  iodine  number 
(Hanus)  obtained  by  the  author  over  a  three-year  period 
was  131.5.     The  acid  value  varied  from  2  to  5.    The 
author  has,  however,  observed  samples  which  had  acid 
values  in  excess  of  8,  the  oils  having  a  characteristic 
rancid  odor  and  not  being  suitable  as  a  paint  vehicle. 

Commercially,  soya  oil  is  obtainable  as  an  extracted 
oil  and  as  an  expressed  oil,  and  the  author  has  not 
been  able  to  find  any  difference  in  their  value  as  a 
paint  vehicle.  For  the  manufacture  of  driers  and 
varnishes,  however,  it  is  necessary  to  specify  when 
purchasing  that  the  oil  shall  not "  break  "  when  heated, 

91 


92         PAINT  VEHICLES,   JAPANS  AND   VARNISHES 


and  such  shipments  should  be  tested  accordingly  by 
the  chemist,  particular  pains  being  taken  to  secure  an 
average  sample  as  certain  extracted  soya  oils  contain  an 
appreciable  amount  of  sediment  (foots)  which  settles 
much  more  rapidly  than  is  the  case  with  linseed  oils. 

In  admixtures  with  linseed  oil  from  North  Ameri- 
can seed  containing  25  per  cent  or  less  of  soya  oil,  the 
iodine  number  of  the  mixture  will  be  in  excess  of  170 
and,  therefore,  would  not  furnish  conclusive  evidence 
of  adulteration.  Such  mixtures  behave  very  similar 
to  linseed  oils  from  South  American  seed,  as  to  drying 
and  hardness  of  the  resulting  film. 

TABLE  XVIII 
126.  Analytical  constants  of  soya  oil l 


Variety 

Specific 
Gravity 
15.  5°  C. 

Saponifi- 
cation 

Iodine 
Number 
Hanus 

Ebony  av  of  7  oils 

926 

193 

126 

Ito  San,  av.  of  19  oils  

.925 

193 

131 

Haberlandt,  av.  of  8  oils  
Manchurian  av  of  33  oils 

.925 
925 

193 
193 

129 
127 

Austin,  av.  of  2  oils  

.924 

192 

127 

127.  Fish  oil  (menhaden  oil).  The  fish  oil  used  in 
the  paint  industry  is  the  variety  obtained  from  the 
menhaden  fish.  Menhaden  oil  in  its  raw  or  natural 
state  is  not  suitable  for  paint  manufacture  due  to  its 
odor,  which  is  not  only  objectionable  during  the  appli- 
cation and  drying,  but  for  a  long  time  afterwards. 
Its  iodine  number  is  very  close  to  that  of  linseed  oil, 
and  when  treated  to  remove  its  objectionable  odor  it 
can  be  used  to  advantage  in  many  industrial  paints 
in  conjunction  with  linseed  oil.  An  oil  with  as  low  an 
acid  value  as  possible  should  be  selected. 

1  Washburn,  N.  D.  Ag.  Exp.  St.  Bulletin  No.  118. 


MISCELLANEOUS  PAINT  AND   VARNISH   OILS        93 


128.  Detection.  Usually  such  mixtures,  when 
strongly  heated,  will  give  off  a  characteristic  fishy 
odor.  In  case  of  doubt  the  Eisenschyml  test l  may  be 
used:  One  hundred  drops  of  the  oil  are  dissolved  in 
6  c.c.  of  a  mixture  containing  equal  parts  of  chloro- 
form and  glacial  acetic  acid.  Bromine  is  added  drop 
by  drop  until  the  brown  coloration  remains.  After 

10  to  15  minutes  the  test  tube  is  placed  in  a  beaker 
containing  boiling  water.     Linseed  oil  and  other  vege- 
table oils,  such  as  China  wood  oil,  cottonseed  oil,  corn 
oil,  etc.,  will  clear  up  completely  within  a  few  seconds, 
while  fish  oils  will  remain  cloudy  and  precipitate  an 
insoluble  bromide  at  the  bottom  of  the  tube  after  a 
short  time.    With  a  little  practice  5  per  cent  of  fish 

011  is  clearly  recognizable. 

In  the  case  of  boiled  linseed  oil  it  is  necessary  to 
remove  the  metallic  constituents  before  adding  the 
bromine.  This  is  preferably  done  by  shaking  with  a 
10  per  cent  solution  of  nitric  acid  saturated  with 
potassium  nitrate. 

TABLE  XIX 

129.  Analytical  constants  of  commercial  menhaden  oils 


No 

Variety 

Specific 
Gravity 
15.  5°  C. 

Acid 
Value 

Saponifi- 
cation 

Iodine 
Number 

1 

2 
3 

4 

Extra  Bleached  ........ 
Pure  Pressed  
Light  Pressed  
Pressed 

.916 
.925 
.924 
925 

12.9 
8.4 
24.0 
8.6 

186 
199 
203 
199 

137 
170 
163 
170 

*, 

Pressed 

927 

9  6 

202 

170 

6 

Treated  Bodied 

972 

4  6 

199 

92 

7 

.964 

2.7 

183 

71 

130.   Lumbang  oil.     This  oil  closely  resembles  tung 
oil  in  appearance  and  in  its  analytical  constants,  but 

1  J.  Ind.  and  Eng.  Chemistry,  February,  1910. 


94         PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

has  an  entirely  different  chemical  constitution  as  it 
does  not  polymerize  with  heat  or  exhibit  anomalous 
dispersion.  When  subjected  to  heat,  it  turns  dark, 
does  not  "  body"  readily  and,  as  far  as  the  author  has 
been  able  to  ascertain,  has  not  found  a  definite  place 
in  the  paint  or  varnish  industries. 

Analysis  of  Cold  Pressed  Lumbang  Oil 

Specific  gravity 0.927 

Acid  value 1.3 

Iodine  number 16. 2 

Saponification  number 192.3 

Refractive  index 1 . 475 

131.  Perilla  oil.     This  oil,  due  to  its  superior  drying 
qualities  and  the  hardness  of  the  resulting  film,  is  find- 
ing an  increasing  use  in  enamels,  varnishes,  and  tech- 
nical paints.    Gardner  gives  the  following  constants 
for  perilla  oil. 

Specific  gravity 937 

Acid  value 4.3 

Iodine  number 193. 3 

Saponification  number 193.4 

Refractive  index 1.4780 

Perilla  oil  frequently  has  a  much  higher  acid  value 
than  linseed  oil;  samples  examined  by  the  author 
have  varied  between  the  limits  of  5  and  11.  Perilla 
oil  bleaches  under  heat  and  takes  on  "  body "  very 
similar  to  a  linseed  varnish  oil.  Its  higher  acid  value 
apparently  does  not  render  it  more  active  toward 
zinc  oxide  or  other  pigments  which  produce  "  livering." 

132.  Reducing  oils.     These  oils  usually  contain  50 
to  65  per  cent  of  mineral  spirits  or  naphtha  and  are 
largely  used  for  reducing  industrial  paste  or  semi- 
paste  paints  to  painting  consistency.     For  such  pur- 
poses, these  oils  have  a  recognized  standing,  especially 
in  the  railroad  trade.    When  linseed  oil  commands  an 


MISCELLANEOUS  PAINT  AND  VARNISH  OILS       95 

abnormally  high  price,  these  oils  are  offered  generally 
on  the  market  as  substitutes  for  linseed  oil,  usually 
with  extravagant  claims  as  to  their  value. 

The  nonvolatile  portion  of  the  better  grades  of  re- 
ducing oils  consists  of  heavily  bodied  linseed  oil,  or 
mixtures  of  such  oil  with  treated  fish  oils  or  tung  oil, 
either  with  or  without  a  small  percentage  of  rosin, 
usually  4  to  7  per  cent.  The  cheaper  grades  contain 
a  much  larger  percentage  of  rosin  or  mixtures  of  rosin 
with  heavy  mineral  oil  bases,  which  cannot  be  regarded 
as  having  a  legitimate  place  in  the  paint  industry. 

The  bodying  of  these  oils  may  be  accomplished  by 
blowing  with  air  at  a  moderate  heat,  by  heat  alone, 
or  by  combination  with  sulphur.  If  sulphur  be  used, 
the  nonvolatile  portion  will  contain  from  5  to  8  per 
cent  by  weight  of  combined  sulphur.  The  presence 
of  sulphur  and  the  amount  present  can  be  determined 
by  following  the  method  given  hi  section  306. 


CHAPTER  X 

SEPARATION   OF  VEHICLE  FROM  PIGMENT 

133.  Preparation  of   sample.     If  the  sample  be  a 
liquid   paint   in   the   unbroken   package,    the   brand, 
manufacturer,  and  guarantee,  or  other  statements  of 
importance  appearing  on  the  label,   should  be  care- 
fully recorded.     The  can  should  also  be  examined  for 
any  evidence  of  leakage,  or  any  markings  indicating 
the  date  of  manufacture.     On  opening  the  package 
the  unfilled  portion  should  be  measured  by  placing  a 
straight  edge  across  the  top  of  the  can  and  measuring 
with  a  ruler  the  distance  downward  to  the  surface  of 
the  oil.    The  gross  weight  of  the  package  should  also 
be  recorded  at  this  time. 

134.  Condition   of   sample.     The  clear  oil   portion 
should  be  carefully  removed  with  the  aid  of  a  pipette 
or  suction  flask,  and  the  surface  of  the  paste  portion 
remaining  should  be  examined  carefully  for  evidence 
of  any  granulation  or  precipitation  of  the  drier  con- 
stituents, which  will  often  form  a  gummy  layer  on 
the  surface  of  the  paste.     The  older  the  sample  the 
more    pronounced    the    precipitation    or    granulation. 
The  condition  of  the  paste  portion  is  readily  ascer- 
tained with  a  steel  spatula,  and  the  degree  of  settling, 
hardening,  and  any  separation  of  the  coarser  particles 
due  to  poor  grinding  should  be  noted. 

135.  Obtaining    a    uniform    sample.     The    paste   is 
then  completely  removed  to  a  larger  can,  known  as 
the  mixing  can,  which  should  be  kept  solely  for  this 


SEPARATION  OF  VEHICLE  FROM  PIGMENT         97 


purpose,  and  stirred  until  smooth.    The  reserved  oil 

portion   is   gradually   added,    with   constant   stirring, 

which  should  be  continued  until    the 

analyst  is  thoroughly  convinced  that  the 

sample  is  uniform  in  composition.     The 

entire  success  of  the  analysis  depends 

upon  securing  a   uniform  sample,    and 

more  analyses  are  incorrect  because  of 

carelessness  in   the   preparation  of  the 

sample  to  be  analyzed  than  from  any 

other  source. 

136.  Weight.      The    weight    of    the 
cleaned  can  subtracted  from  the  gross 
weight  gives  the  net  weight  of  the  sample. 
The  can  is  then  filled  to  the  height  occu- 
pied by  the  sample,  as  noted  above,  with 
water  from  a  carefully  graduated  measure, 
thus  giving  the  net  volume  of  the  paint. 
The  can  is  then  filled  to  the  brim  with  a 
measured  amount  of  water  and  the  ca- 
pacity of  the  can  recorded. 

137.  Separation  of  the  pigment.  Much 
difficulty  is  often  experienced  in  extract- 
ing the  vehicle  from  the  pigment,  due  to 
the  fineness  of  the  pigment  particles  and 
the  ease  with  which  they  pass  through 
the  walls  of  the  extraction  tubes.    This 
difficulty,  however,  may  be  avoided  by 
the  use  of  the  apparatus  illustrated  here- 
with (Fig.  6).     The  extraction  thimble, 
containing  a  filter  folded  cylindrically, 

is  dried  in  the  hot-water  oven  for  thirty  minutes,  weighed, 
and  10  to  15  grams  of  the  sample  weighed  into  it, 
extracted  with  ether  for  24  to  36  hours,  dried,  and 


FIG.  6. 

EXTRACTION 
APPARATUS. 


98        PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

weighed  again.  The  loss  in  weight  represents  the 
vehicle,  and  the  residue  remaining,  the  pigment,  which 
is  reduced  to  a  fine  powder  and  kept  tightly  stoppered 
until  examined.  Any  casein  or  similar  product  in  the 
paint  will  remain  unextracted  by  the  ether  and  unless 
detected  will  interfere  with  the  proper  analysis  of  the 
pigment.  With  very  finely  divided  pigments,  like 
Prussian  blue,  a  thickly  padded  Gooch  crucible  may 
be  used;  the  successive  extractions  may  be  decanted 
into  it,  using  a  strong  suction  and  refilling  the  Gooch 
before  it  sucks  dry. 

138.  Extraction   with   acetone.     If   the   paint   con- 
tains a  considerable  percentage  of  water  the  extrac- 
tion can  be  best  accomplished  with  the  use  of  a  good 
grade  of  acetone.    Many  chemists  prefer  a  solvent 
prepared  by  mixing  50  parts  benzol,  30  parts  wood 
alcohol,  and  20  parts  refined  acetone. 

139.  Removal     of     vehicle     in    quantity.     Another 
method  of  obtaining  sufficient  vehicle  from  a  liquid 
paint  for  the  determination  of  the  volatile  oils,  the 
quality  of  the  linseed  oil,  etc.,  is  to  fill  a  tall  cylinder 
with  such  of  the  sample  as  is  not  needed  for  the  water 
estimation  (100  to  150  grams)  and  for  obtaining  the 
free  pigment,  corking  it  tightly,  and  placing  it  in  a  tall 
copper  can  filled  with  water  heated  to  about  70°  C. 
By  reducing  the  viscosity  of  the  oil  in  this  manner  the 
pigment  will  settle  quite  rapidly,  and  in  24  hours,  if 
the  temperature  is  maintained  at  70°  C.,  sufficient  oil 
may  be  siphoned  off  with  aid  of  the  suction  pump. 

140.  Use    of    centrifuge.     By    far    the    most    con- 
venient   method    of    obtaining   sufficient    vehicle   for 
examination  is  by  centrifuging  the  paint.     In  the  aver- 
age laboratory  an  electric  centrifuge  is  the  most  con- 
venient type.    The  cylinders  used  may  be  of  glass, 


SEPARATION  OF  VEHICLE  FROM  PIGMENT         99 

but  preferably  of  aluminum,  as  the  pressure  on  the 
ends  is  often  severe  when  the  centrifuge  is  hi  motion. 
The  bottoms  of  the  cylinders  should  be  removable, 


FIG.  7. 


being  screwed  onto  the  cylinder.  This  permits  of  the 
easy  removal  of  the  precipitated  paint  and  the  rapid 
cleaning  of  the  cylinders. 


100      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

141.  Balancing  the  cylinders.     It  is  necessary  that 
the  cylinders  opposite  one  another  be  evenly  balanced, 
and  it  is  always  advisable  to  balance  up  the  cylinders 
on  the  scales  before  placing  them  in  the  centrifuge. 
The  cylinders  should  be  tightly  corked  to  prevent  loss 
by  evaporation  of  the  volatile  thinners,  and  live  steam 
admitted  into  the  centrifuge  chamber  sufficient  to  heat 
the  contents  of  the  tubes  to  about  70°  C.    In  the 
majority  of   cases   the  pigment  will   be  thrown   out 
rapidly  and  cleanly  and,  by  using  a  number  of  cylin- 
ders,  an  ample  amount   of   the   oils   may  be   easily 
obtained. 

142.  Power  centrifuges.     In  the  factory  laboratory, 
where  the  steam  pressure  is  always  available,  an  ordi- 
nary Babcock  butter-fat  tester  can  be  conveniently 
used,  the  steam  leakage  into  the  upper  chamber  being 
sufficient  to  keep  the  tubes  warm  enough  to  insure 
the  rapid  precipitation  of  the  pigment.     The  machine 
selected  for  this  purpose  should  be  very  strongly  made. 
One  of  the  safest  and  most   satisfactory  centrifuges 
on  the  market  is  that  illustrated  in  this  connection 
(Fig.  7),  manufactured   by  the   International  Instru- 
ment Company,  Cambridge,  Mass. 

143.  Centrifugal  force  in  centrifuges 

Centrifuge  Head    ^fa£a<i!*;jf     Rotating        Force  in  Lbs.  per  Lb.  in  Revolutions  per 
Rev.  per  Minute      jJcc       Diameter  Minute 

in  Cm. 

8-place   com-   —  —  600  1200  1800  2400  3000 

bination...   500  43  86  344  744  1380  2150 

250  40  80  320  720  1280  2000 

100  44  88  352  792  1480  2200 

50  38  76  304  684  1216  1900 

EXAMPLE  :  A  cup,  weighing  2  pounds,  at  a  speed  of 
3000  r.p.m.,  would  exert  a  stress  of  4000  Ibs.  on  its 
trunnions. 


SEPARATION  OF  VEHICLE   FROM   PIGMENT       101 

144.  Cushioning   of   glassware.     A  rubber  cushion 
should  be  supplied  for  each  tube.     Place  a  little  water 
in  the  metal  tube,  insert  the  glass  tube,  press  down, 
and  allow  the  water  to  overflow  the  metal  tube.    If 
this  care  is  taken  in  the  matter  of  balancing  pressures 
and  of  cushioning  there  should  be  very  little  breakage 
of  glassware. 

145.  Rapid  separation  of  pigment.     If  only  the  pig- 
ment is  desired  the  separated  oil  may  be  poured  off 
and  the  precipatated  pigment  stirred  up  with  benzine, 
centrifuged,  and  the  operation  repeated  twice  more. 
This  will  insure  the  removal  of  practically  all  the  lin- 
seed oil,  only  a  trace  remaining.    When  dried  the  pig- 
ment should  receive  an  especially  careful  mixing,  as 
the  centrifuging  causes  the  pigments  to  settle  to  a 
certain  extent  according  to  their  specific  gravities. 

146.  Separation  of  the  oil  for  determination  of  its 
chemical  constants.     The  chief  consideration  in  remov- 
ing the  oil  for  the  determination  of  the  iodine  number, 
etc.,  is  to  prevent  any  oxidation  of  the  oil  during  the 
recovery  process,  a  necessity  not  fully  appreciated  by 
many    commercial    analysts.    The    vehicle    obtained 
from  the  extraction  described  in  section  137  is  usually 
insufficient  for  this  purpose,  and  the  following  pro- 
cedure, used  in  many  railroad  laboratories,  has  been 
found  very  satisfactory. 

147.  Procedure.    A  quantity  of  the  paint  sufficient 
to  yield  about  30  c.c.  of  vehicle  is  weighed  into  one 
or  more  centrifuge  bottles,  and  a  sufficient  quantity 
of  redistilled  petroleum  ether  (distilling  under  60°  C.) 
is  added.     Close  the  bottle  tightly  and  shake  until  a 
uniform  mixture  is  obtained.     Centrifuge  until  a  good 
separation  is  obtained.     Pour,  or  siphon  off,  the  clear 
supernatent  solution  on  to  a  filter  and  into  a  round- 


102      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

bottom  distillation  flask  that  will  be  about  three- 
fourths  full.  Distill  the  greater  portion  of  the  petro- 
leum ether,  using  an  oil  bath.  Insert  a  steam  distilling 
tube,  raise  the  oil  bath  to  120°  C.  and  pass  a  rapid 
current  of  steam  until  the  volatile  thinners  are  all 
over  and  at  once  pour  the  residual  oil  into  a  separatory 
funnel.  Rinse  out  the  flask  with  sulphuric  ether 
(alcohol  free),  using  a  total  of  about  75  c.c.  Shake 
and  allow  to  stand  until  a  sharp  separation  is  obtained. 
Draw  off  the  water,  transfer  the  ether  solution  com- 
pletely to  a  small  flask,  distill  off  the  larger  part  of 
the  ether,  transfer  again  to  a  weighed  beaker  and 
drive  off  the  remaining  ether  on  a  steam  bath  as 
rapidly  as  possible,  being  careful  to  prevent  its  foam- 
ing over.  Cool  immediately  and  weigh.  Transfer  to 
a  small  bottle  of  closely  the  same  volume  as  the 
volume  of  the  oil  obtained,  cork  tightly  and  keep 
in  a  dark  place  until  ready  for  further  examination. 
It  is  practically  necessary  that  the  analyst  constantly 
watches  the  final  evaporation  and  notes  the  point  at 
which  the  ether  is  completely  gone,  as  further  heating 
will  rapidly  lower  the  iodine  value  of  the  oil. 

148.  Oxidation.  Boughton l  found  that  portions  of 
the  oil  extracted  from  a  white  lead  paste  heated  for 
2  hours  at  98°-99°  C.  in  ah-,  in  hydrogen  and  in 
carbon  dioxide  gave  the  following  iodine  numbers: 
173,  182,  and  180.  Likewise  a  prepared  linseed  oil 
containing  3.23  per  cent  of  lead  in  combination  as 
linoleate,  when  heated  at  the  same  temperature  for 
2  hours  and  for  4  hours  in  air,  gave  158  and  143 
against  180  and  174  in  carbon  dioxide,  the  prepared 
oil  itself  having  an  iodine  number  of  177.  A  pure 
linseed  oil  having  an  iodine  number  of  179  was  dis- 
1  J.  Ind.  and  Eng.  Chem.,  5,  282. 


SEPARATION  OF  VEHICLE  FROM  PIGMENT       103 

solved  in  ether,  the  bulk  of  the  ether  removed  by 
distillation,  and  the  oil  heated  at  98°-99°  C.  gave  the 
following  results: 

TABLE  XX 


Gas 
Air            

Time 
2  his. 

Iodine  Number 
174 

Air 

4    " 

168 

Hydrogen         

2    " 

177 

Hydrogen  
Carbon  dioxide.  .  . 

4    " 
..  4    " 

178 
179 

149.  Total   vehicle.     If    the   vehicle    contains   any 
considerable    percentage    of    hard    varnish    resins,    it 
will  be  advisable  to  use  only  sulphuric  ether  in  the 
entire  operation,  in  order  to  prevent  the  gums  from 
precipitating. 

The  pigment  remaining  in  the  centrifuge  bottles  can 
be  thoroughly  stirred  with  more  ether,  until  all  lumps 
are  broken  up,  and  centrifuged  again,  repeating  the 
operation  until  either  three  or  four  changes  of  ether 
have  been  used,  as  may  be  necessary.  The  ether  is 
completely  distilled  off  and  the  percentage  of  the 
residual  oil  plus  the  percentage  of  oil  obtained  in  the 
first  extraction  is  subtracted  from  100,  giving  the  per- 
centage of  pigment. 

150.  Agricultural  paste   paints.     Paste  paints   con- 
taining para  red  are  best  extracted  with  petroleum 
ether,  if  the  percentage  of  para  color  is  to  be  deter- 
mined   in    the    extracted    pigment.     Frequently    the 
darker  shades  of  para  reds  contain  soaps  or  sulpho- 
nated  oils  used  to  develop  the  color.    When  present, 
they  will  be  extracted  along  with  the  vehicle  when 
sulpfturic  ether  is  used,  and  also  to  some  extent  when 
petroleum   ether   is   selected   as   the   solvent.    These 
soaps  and  oils  slow  up  the  drying  of  the  vehicle  to  a 
very  appreciable  extent. 


104      PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

151.  Graining  compounds  and  distemper  colors. 
The  vehicle  portion  of  these  products  is  essentially 
water  or  a  mixture  of  water  and  alcohol  to  prevent 
freezing  in  cold  weather.  A  small  percentage  of  dex- 
trine or  a  similar  binder  may  be  present.  The  vehicle 
may  be  removed  by  distillation,  using  an  oil  bath, 
and  the  alcohol  determined  from  the  gravity  of  the 
distillate. 


CHAPTER  XI 

ESTIMATION  OF  WATER  IN  PAINTS 

152.  Occurrence.     A  fraction  of  1  per  cent  of  water 
may  occur  normally  in  the  vehicle.    A  small  percent- 
age, 1  to  3  per  cent,  may  be  incorporated  into  the 
paint  by  the  manufacturer  under  the  belief  that  it 
secures  better  penetration  when  applied  to  surfaces 
that  are  slightly  damp,  and  also  that  it  will  prevent 
the  pigment  from  settling  and  becoming  hard  hi  the 
can.     Oftentimes,  however,  large  quantities  are  intro- 
duced  for   the  purpose   of   cheapening   the  product. 
The  water  may  be  added  to  the  paint  and  prevented 
from  separating  out  by  forming  an  emulsion  with  the 
oil  by  the  aid  of  an  alkali  or  alkali  salt,  or  by  grinding 
it  into  the  pigment,  using  an  adhesive  such  as  glue 
or  casein.    In  the  first  case  the  nature  of  the  ash  left 
on  burning  some  of  the  separated  vehicle  will  indicate 
whether  an  alkali  has  been  used  or  not.    In  the  second 
case  the  vehicle  will  yield  less  than  1  per  cent  of  water 
when  distilled  with  a  dry,  inert  substance,  such  as 
sublimed  lead,  as  the  water  remains  with  the  pigment. 

153.  Conclusions.    Analytical  results  showing  the 
presence  of  water  in  a  paint  product,  even  in  con- 
siderable quantity,  is  not  proof  positive  that  the  water 
was   added   intentionally   as   such.    Many   pigments 
carry  considerable  hygroscopic  moisture.     The  author 
has  analyzed  shipments  of  leaded  zincs  hi  which  the 
moisture  content  varied  from  0.08  per  cent  to  1.68 
per  cent  in  the  same  shipment;    ultramarine  blues 

105 


106       PAINT   VEHICLES,   JAPANS  AND   VARNISHES 

were  found  to  contain  as  high  as  2.37  per  cent  mois- 
ture; ochers  and  raw  siennas  as  much  as  3  per  cent 
and  China  clays  as  high  as  6  per  cent.  Unless  ground 
very  hot  in  the  paint  mills,  the  hygroscopic  moisture 
present  in  the  pigments  used  will  be  found  in  the 
ground  product  and,  if  high,  will  in  many  instances, 
especially  when  varnishes  are  used,  cause  serious 
trouble  from  livering.  The  paint  chemist  should 
watch  incoming  shipments  which  are  hygroscopic  in 
nature  and  carefully  check  the  percentage  of  moisture 
present. 

154.  Presence    of    water    in    containers.     Recently 
there  have  been  numerous  complaints  on  the  part  of 
paint  and  varnish  manufacturers  regarding  water  in 
shipments  of  naphtha,  both  tank  cars  and  drums,  pre- 
sumably due  to  the  carelessness  of  the  refiners  in  not 
properly   cleaning   the   tanks   and   drums   before   re- 
filling.    As  these  containers  are  usually  emptied  by 
drawing  from  the  bottom,  there  is  appreciable  danger 
that  the  water  will  find  its  way  into  paint  and  varnish 
products.     In  the  latter  case  there  is  serious  danger 
from  fire  and  injury  to  the  workmen. 

155.  Combined    water.     Several   pigments    contain 
combined  water  which  is  easily  split  off  when  sub- 
jected to  even  moderate  heat,  and  an  analysis  of  a 
paint  containing  these  pigments  might  indicate  the 
presence  of  uncombined  water  when  in  fact  the  water 
was  not  present  in  the  paint  as  such.    Prussian  and 
Chinese   blues   examined   by   the   author   have   been 
found  to  contain  2  to  6  per  cent  of  combined  water, 
white  lead  2  to  3  per  cent,  gypsum  19  to  21  per  cent. 
Therefore  the  chemist  in  making  analyses  of  paints 
containing  these  pigments  should  be  especially  careful 
as  to  reporting  the  presence  of  water. 


ESTIMATION   OF  WATER   IN  PAINTS  107 

156.  Determination    of    water    with    amyl    reagent. 
This  method  has  been  found  exceedingly  satisfactory 
by  the  author  and  much  more  accurate  than  the  dis- 
tillation with  toluene.     The  components  of  the  amyl 
reagent  —  amyl  acetate  and  amyl  valerianate  —  must 
be  free  from  amyl  alcohol  and  other  water  soluble 
impurities.    Fritsche  Brothers,  New  York  City,  have 
furnished  the  most  satisfactory  article  the  author  has 
been   able    to    obtain.    Each    component    should   be 
washed  with  at  least  two  changes  of  distilled  water, 
which  can  be  readily  accomplished  in  a  large  separa- 
tory  funnel  and  then  redistilled,  rejecting  the  first  20 
per  cent  of  the  distillate.     The  reagent  is  obtained  by 
mixing  5  volumes  of  the  purified  amyl  acetate  with 
1  volume  of  the  purified  amyl  valerianate. 

157.  Procedure.   About  100  grams  of  the  thoroughly 
stirred  sample  of  paint  are  weighed  into  a  flat-bot- 
tomed 200-250-c.c.   side-necked  distilling  flask.    Add 
75  c.c.  of  the  amyl  reagent  and  with  a  gentle  rotary 
motion  secure  a  thorough  mixing  of  the  contents  of 
the  flask.     Connect  with  an  upright  condenser   and 
distill    over    about    60    c.c.    of    the    reagent    into    a 
cylinder  graduated  into  tenths  of  cubic  centimeters. 
When  the  larger  portion  of  water  has  passed   over, 
the   upper   portion   of   the  flask  should  be  warmed 
gently  with  the  naked  flame,  in  order  to  expel  the 
small  portion  of  moisture  that  will  have  collected  on 
the  sides  of  the  flask.    The  distillation  should  then  be 
continued  until  the  requisite  amount  of  reagent  has  dis- 
tilled over.    The  percentage  of  water  can  then  be  easily 
read  off  from  the  graduated  cylinder  and  the  contents  of 
the  distilling  flask  will  be  sufficiently  liquid  to  insure  easy 
removal.     With  paints  high  in  volatile  oils  the  volume 
of  the  distillate  should  be  increased  to  at  least  75  c.c. 


108      PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

A  half-pint  or  pint  varnish  can  heated  in  an  oil 
bath  is  preferable  to  a  glass  distilling  flask,  as  the 
danger  of  breakage  is  eliminated  and  the  can  may  be 
discarded  when  the  distillation  is  completed.  Several 
hundred  analyses  made  by  this  method  on  pulp  leads 
and  paste  paints  show  that  the  combined  water  in 
white  lead  is  not  split  off,  that  Prussian  blue  gives  off 
practically  all  its  water  of  combination  and  gypsum 
yields  about  75  per  cent  of  the  water  of  crystallization 
present. 


CHAPTER  XII 

WATER  EMULSIONS  AND   EMULSIFIERS 

158.  Occasionally  it  devolves  upon  the  paint  chem- 
ist  to   determine   the  agents   used  for  securing  and 
maintaining  the  emulsion  of  oil  and  water  in  paints 
and  for  preventing  the  hardening  of  paste  goods,  such 
as  combination  leads,  etc. 

159.  Necessity  of  an  emulsion.     The  use  of  water 
in  paints  has  been  a  much  discussed  question.    The 
majority  of  paint  manufacturers  have  maintained  that 
the  addition  of  a  certain  amount  of  water  is  essential 
for  the  preparation  of  a  high  grade  paint,  in  order  to 
prevent  the  pigments  from  settling  hard  in  the  bottom 
of  the  can,  in  which  case  there  is  much  trouble  and 
difficulty   experienced   in   "  breaking   up "   the   paint 
when  desired  for  use.    As  regards  this  contention  the 
author  believes  the  manufacturers  are  in  the  right, 
that  better  results  are  secured  by  the  use  of  a  small 
percentage  of  water  in  a  paint  high  in  lead  and  zinc. 
The  line  of  demarcation,  however,  between  the  amount 
that  can  be  considered  legitimate  for  this  purpose  and 
that  which  may  be  considered  as  added  for  adultera- 
tion or  cheapening,  is  by  no  means  well  defined.    The 
author's  experience  has  led  him  to  believe  that  the 
true  purpose  of  the  addition  of  the  water  is  best  served 
by  using  an  amount  not  exceeding  3  per  cent  of  the 
vehicle  present,  and  that  any  amount  in  excess  of  5 
per  cent  may  be  regarded  as  having  been  added  for 
cheapening  the  product. 

109 


110      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

160.  Impairment  of  service  value.     The  addition  of 
any  considerable  percentage  of  water  unquestionably 
reduces  the  service  value  of  a  paint,  but  it  is  more 
often  the  materials  used  with  the  water  to  obtain 
the  emulsion  that  cause  the  greater  harm.    Any  sub- 
stance which  is  astringent  hi  its  action,  or  which  will 
cause  a  partial  saponification  of  the  oil,  or  bring  about 
reactions  between  the  oil  and  the  pigments  present, 
materially  reduces  the  wearing  value  of  such  paint 
and  the  author  can  only  regard  the  addition  of  such 
substances  as  willful  adulteration. 

Strongly  emulsified  paints,  especially  the  cheaper 
grades,  work  a  further  deception  on  the  consumer,  un- 
less he  is  advised  as  to  what  quality  he  is  purchasing, 
in  that  such  paints  do  not  cover  nearly  as  large  areas 
per  gallon  as  does  a  representative  high  quality  paint, 
and  therefore  the  economy  is  more  apparent  than  real 
in  the  purchase  of  such  emulsion  paints. 

161.  Deterioration.     Most     emulsion    paints,     i.e., 
those  containing  over  5  per  cent  of  water,  will  not 
keep  in  a  usable  condition  when  submitted  to  storage 
for  a  considerable  interval  of  time.     Certain  reactions 
take  place  between  the  vehicle  and  the  pigment  which 
cause  a  gradual  thickening  of  the  paint,  until  in  many 
instances  all  traces  of  the  vehicle  have  apparently 
disappeared.    The  chemical  actions  set  up  and  their 
cause  are  discussed  in  a  subsequent  chapter. 

162.  Classification.     We  may  divide  the  emulsify- 
ing agents  into  two  classes,  —  those  which  are  inert 
and  those  which  are  more  or  less  active. 

The  first  class  comprises  such  substances  as: 

Glue 

Casein  (containing  no  free  alkali) 


WATER  EMULSIONS  AND  EMULSIFIERS  111 

Oleates  of  lead  and  alumina 

Stearate  of  alumina 

Turpentine 

Alcohol 

Glycerine 

Starch 

The  second  class : 
Chloride  of  lime 
Sulphate  of  zinc 
Silicate  of  soda 
Carbonate  of  soda 
Caustic  soda 
Lead  acetate 
Borax 
Phosphate  of  soda 

163.  Glue  and  casein.    The  presence  of  glue  and 
casein  may  be  detected  by  heating  a  small  portion  of 
the  pigment,  secured  by  extraction  with  ether,  in  a 
small  porcelain   crucible  and  noting  the  odor  given 
off,  and  comparing  the  same  with  that  obtained  by 
heating  a  mixed  pigment  to  which  a  little  glue  or 
casein  has  been  added.     The  amount  present  may  be 
determined    by    running    a    nitrogen    determination 
according  to   the   Kjeldahl   method  and  multiplying 
the  nitrogen  content  by  6.37.    About   10  grams  of 
pigment  should  be  used. 

164.  Oleates   and   stearates   of  lead  and  alumina. 
Oleate  of  lead  is  but  rarely  used,  while  the  use  of 
stearate  is  quite  common.    The  present  methods  for 
detection  and  estimation  are  unsatisfactory,  as  paints* 
containing  white  lead  carbonate,  sulphate  or  red  lead, 
form  lead  soaps  on  standing  with  the  linseed  oil,  which 
cannot  be  readily  separated  from  the  added  soaps. 


112      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

Stearate  of  alumina  is  frequently  used,  being  present 
in  solution  in  the  vehicle.  A  quantitative  estimation 
of  the  amount  of  alumina  present  in  the  ash  obtained 
from  incinerating  the  vehicle  is  presumptive  evidence 
of  the  presence  of  a  fatty-acid  salt  of  alumina.  Stea- 
rate of  alumina  is  frequently  found  in  flat  wall  finishes. 

165.  Turpentine.     Turpentine   is   by   far   the   best 
emulsifier  to  use,  as  it  is,  itself,  a  normal  constituent 
of  paint.     The  formation  of  a  water-turpentine  emul- 
sion can  best  be  accomplished  by  mixing  into  a  paste 
a  nonsettling  pigment  like  asbestine  (magnesium  sili- 
cate) or  China  clay  with  a  little  linseed  oil,  adding 
water  and  turpentine.    The  following  affords  a  base 
of  uniform  consistency  and  composition  which  can  be 
added  to  any  mix  of  pigments  in  any  desired  proportion: 

150  Ibs.  China  clay, 
150  Ibs.  asbestine  pulp, 
21  gals,  water, 

4  gals,  linseed  oil, 

2  gals,  turpentine. 

A  formula  like  the  above  possesses  much  merit,  as 
both  China  clay  and  asbestine  pulp  are  especially 
valued  for  their  nonsettling  qualities,  and  acting  in 
conjunction  with  the  water  will  prevent  any  reason- 
able combination  of  pigments  from  settling  hard,  even 
when  used  in  small  quantity. 

166.  Glycerine.     Glycerine    and    starch    are    often 
used  in  conjunction  with  each  other,  not  only  for  the 
purpose   of   introducing   water   but   to   prevent   the 
hardening  of  paste  goods,  such  as  combination  leads. 
The  following  working  formula  illustrates  their  use: 

500  Ibs.  white  lead, 

300  Ibs.  zinc  oxide  "  xx," 


WATER  EMULSIONS  AND   EMGLSIFIERS  113 

150  Ibs.  white  mineral  primer, 
200  Ibs.  barytes, 

|  oz.  ultramarine  blue, 

|  Ib.  glycerine, 

1  Ib.  starch  (powdered), 
15|  gals,  linseed  oil. 

Glycerine  is  also  used  in  admixture  with  denatured 
alcohol  and  water  to  prevent  settling  and  hardening. 

167.  Chloride  of  lime  and  sulphate  of  zinc.     These 
products,  while  powerful  emulsifying  agents,  are  the 
most  harmful  to  use  owing  to  their  astringent  action 
on  linseed  oil.     Just  what  the  chemical  reactions  are 
which  they  enter  into  are  difficult  to  determine,  and 
it  is  difficult  if  not  impossible  to  prove  their  presence 
in  the  majority  of  paints  in  which  they  are  used, 
except  as  may  be  indicated  by  failure  to  give  satis- 
factory service  value. 

168.  Carbonate  of  soda  and  caustic  soda.    /These 
two  substances  are  perhaps  more  generally  used  than 
any  of  the  others.     The  conversion  of  a  portion  of  the 
linseed  oil  into  a  water-soluble  soap  necessarily  results 
in  decreasing  the  life,  or  wearing  value,  of  the  paint 
in  which  the  above  ingredients  may  be  used.     Their 
presence  may  be  judged  by  incinerating  a  small  por- 
tion of  the  vehicle  and  examining  the  nature  of  the 
ash  obtained. 

169.  Acetate  of  lead.     The  use  of  acetate  of  lead 
as  an  emulsifying  agent  cannot  be  commended.     It 
acts  on  the  oil,  although  its  effect  is  probably  not  so 
severe  if  it  is  incorporated  into  the  paint  subsequent 
to  its  passage  through  the  mill  as  it  would  be  if  it  were 
added   in   the   original   mix.     A  warm   mill   running 
under  a  suitable  tension  will  cause  any  appreciable 


114      PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

amount  of  acetate  of  lead  to  act  vigorously  on  the 
linseed  oil,  causing  a  more  or  less  pronounced  harden- 
ing in  the  package. 

170.  Borax  and  phosphate  of  soda.  These  prod- 
ucts are  usually  used  with  carbonate  of  soda  or 
caustic  soda. 

The  following  is  a  much  used  formula: 

Phosphate  of  soda 6  Ibs. 

Bicarbonate  of  soda 6  Ibs. 

Water... 


Both  of  these  substances  can  be  detected  by  the 
well-known  qualitative  tests. 


CHAPTER  XIII 

DETERMINATION   OF  VOLATILE  THINNER 

171.  Definition.1     The   American  Society  for  Test- 
ing Materials  has  denned  "volatile  thinner"  as  "all 
that  liquid  portion  of  a  paint,  water  excepted,  which 
is  volatile  in  a  current  of  steam  at  atmospheric  pres- 
sure."   The   accurate    determination   of   the   volatile 
thinner  in  a  paint,  enamel,  or  varnish  presents  diffi- 
culties that  are  not  readily  apparent  or  indicated  by 
the  above  official  definition. 

Linseed  oil  always  contains  a  varying  quantity 
of  free  fatty  acids  which  are  very  appreciably  volatile 
with  steam  at  130°-140°  C.  In  a  specification  pure 
linseed  oil  semi-paste  paint  the  author  has  found  as 
high  as  2  per  cent  volatile  thinner  which  on  examina- 
tion was  found  to  be  composed  of  fatty  acids  from  the 
oil  used.  A  heat  bodied  linseed  oil  having  an  acid 
value  of  24  to  30,  such  as  is  frequently  used  in  enamel 
liquids  and  varnishes,  contains  a  proportionately  larger 
percentage  of  volatile  fatty  acids  than  raw  linseed 
oil.  Damar  gums  also  contain  1  to  2  per  cent  of  oil, 
volatile  at  130°  C. 

172.  Increased  use  of  heavy  naphthas.    As  long  as 
the  paint  and  varnish  industries  confined  their  re- 
quirements for  volatile  thinners  to  gum  spirits  of  tur- 
pentine and  to  the  established  grades  of  P.  and  V.  M. 
naphthas,  distillation  with  steam  at  100°  C.  could  be 
relied  upon  to  remove  all  of  the  volatile  thinner  pres- 

1  A.  S.  T.  M.  Standards,  1918,  page  748. 
115 


116      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

ent,  unless  the  product  was  a  paste,  semi-paste  or  short 
oil  varnish,  in  which  case  an  appreciable  percentage  of 
volatile  thinner  was  retained  in  the  product  examined, 
due  to  heavy  consistency  of  the  mass. 

The  above  mentioned  thinners  have  been  largely 
replaced  by  heavy  naphthas,  which  evaporate  much 
more  slowly,  as  they  contain  a  considerable  percent- 
age of  hydrocrabons  distilling  above  200°  C.  These 
high  boiling  point  fractions  are  volatile  with  steam 
at  100°  C.  only  under  prolonged  treatment,  and  if  the 
residual  mass  is  gummy  or  pasty  a  considerable  per- 
centage will  remain  unvolatilized,  causing  a  very  ap- 
preciable error  in  the  determination.  Distillation  by 
direct  heat  requires  a  temperature  sufficiently  high  to 
produce  decomposition  products  in  sufficient  quanti- 
ties to  cause  serious  error  and  contaminate  the  distil- 
late obtained. 

173.  Procedure  developed  by  the  author.  To  meet 
the  above  mentioned  difficulties  the  author  has  de- 
veloped the  following  procedure.  A  weighed  quantity 
of  the  product  to  be  examined,  containing  approxi- 
mately 100  c.c.  of  vehicle,  is  weighed  by  difference 
into  a  one-half-gallon  varnish  can,  or  other  suitable 
container,  and  about  75  g.  paraffine  wax  (m.p.  125°- 
130°  F.)  added,  the  function  of  the  wax  being  to 
keep  the  mass  in  a  freely  fluid  condition  during  the 
entire  volatilization  of  the  thinner.  The  can  is  im- 
mersed for  about  two-thirds  its  height  in  an  oil  bath, 
kept  between  the  limits  of  130°  C.  and  135°  C.  The 
can  is  provided  with  a  steam-distilling  tube  extending 
to  the  bottom  and  a  suitable  source  of  live  steam.  A 
distilling  bulb  is  used  having  an  additional  opening 
in  the  lower  part  of  the  stem  and  also  an  extra  open- 
ing near  the  top  of  the  inner  tube  in  the  bulb,  to  pre- 


DETERMINATION  OF  VOLATILE  THINNER   117 

vent  drops  of  the  vehicle  which  may  collect  in  the 
stem  or  bulb  from  being  carried  over  mechanically 
with  the  distillate.  The  distilling  bulb  is  connected 
with  a  vertical  coil  condenser  discharging  into  a 
partially  filled  100-c.c.  burette  with  a  rubber  tube 
connection  serving  as  a  siphon  overflow,  thus  permit- 
ting the  aqueous  distillate  to  pass  continuously  into 
a  16-oz.  graduate. 

To  completely  remove  all  of  the  volatile  thinner  it 
is  usually  necessary  to  continue  the  distillation  until 
32  oz.  of  aqueous  distillate  have  been  collected.  This 
aqueous  distillate  will  carry  with  it  a  slight  quantity  of 
the  volatile  thinner,  and  considering  the  large  volume 
of  the  former  as  compared  with  the  latter,  the  error 
arising  from  this  cause  is  often  considerable.  It, 
however,  becomes  negligible,  if  the  aqueous  distillate 
from  a  previous  determination  of  volatile  thinner  be 
used  for  generating  the  steam. 

The  volume  of  thinner  is  noted,  after  the  adhering 
drops  of  water  on  the  wall  of  the  burette  have  been 
dislodged  with  a  stiff  wire.  The  gravity,  distillation 
and  polymerization  can  be  determined  in  the  usual 
manner.  If  however  the  nonvolatile  vehicle  contains 
a  considerable  percentage  of  linseed  oil,  it  will  be  ad- 
visable to  redistil  the  thinner  to  free  it  from  the 
fatty  acids  before  subjecting  it  to  the  polymerization 
test. 

174.  Aromatic  hydrocarbons  and  olefins.  The  per- 
centage of  benzole  and  its  homologues  can  be  deter- 
mined by  the  following  method.1  A  mixture  of  80 
volumes  of  concentrated  sulphuric  acid  and  20  volumes 
of  fuming  sulphuric  acid  is  prepared,  and  25  c.c.  of  the 
sample  and  25  c.c.  of  the  mixture  are  shaken  vigor- 

1  Kramer  and  Bottcher,  Gewerbefleiss,  1887. 


118      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

ously  for  15  minutes  in  a  100-c.c.  flask  with  a  suitably 
graduated  neck.  After  30  minutes,  concentrated  sul- 
phuric acid  (not  the  mixture)  is  added  until  the  oily 
residue  can  be  measured  in  the  neck.  The  volume  of 
unattacked  hydrocarbons  is  read  after  standing  for  an 
hour,  or  when  the  volume  no  longer  increases.  Allow- 
ance should  be  made  for  the  average  percentage  of 
hydrocarbons  in  petroleum  thinners  that  react  with 
the  acid,  as  described  in  Chapter  XVII,  Comparative 
Analysis  of  Black  Baking  Japans.  If  extreme  accu- 
racy is  required  the  procedure  developed  by  Thole  may 
be  followed.  Journal  Soc.  Chem.  Industry,  Vol.  38, 
No.  4,  p.  39. 

175.  Results.  The  following  table  (XXI)  gives  the 
results  obtained  in  the  author's  laboratory  with  vari- 
ous volatile  thinners.  The  mineral  spirits  used  con- 
formed to  government  specifications  but  came  just 
within  the  upper  limits  as  to  distillation  and  residue 
on  evaporation.  The  amount  used  in  each  case  was 
a  known  quantity  and  due  precautions  were  taken  to 
avoid  loss  prior  to  the  distillation.  Sixty  grams  of 
parafnne  wax  (m.p.  130°  F.)  were  used  as  the  diluent 
in  each  determination. 

Tests  made  with  the  ordinary  types  of  distilling 
bulbs  show  that  1  to  4  per  cent  of  the  nonvolatile 
vehicle  is  carried  over  mechanically  with  the  volatile 
thinner  in  paint  products  containing  a  large  percent- 
age of  linseed  oil. 


DETERMINATION  OF  VOLATILE  THINNER   119 


TABLE  XXI 
176.  Recovery  of  volatile  thinners 

C.c.  volatile  thinner  recovered  with  each  8  oz.  aqueous  distillate 


Material 

1st 
8  oz. 

2d 
8  oz. 

3d 

8  oz. 

4th 

8  oz. 

Total  c.c 
volatile 
obtained 

Total  c.c. 
volatile 
present 

Hardened  Rosin  
Treated  Tung  Oil  (100  g.) 
Treated  Tung  Oil,  Min- 
eral Spirits  
Treated  Linseed  Oil.  .  . 
Raw  Oil,  av.  of  5  ship- 
ments   
Reducing  Oil  (L.  O.  and 
M.  Spts.) 

62.0 
0.4 

0.3 
60.3 

2.4 

0.2 

0.2 

2.7 

0.7 
0.1 

0.2 
0.7 

0.4 
0.1 

0.0 
0.7 

0.0 

0.3 

65.5 
0.8 

0.7 
64  4 

0.0 
0.0 

o.'o 

0.0 

64  8 

Varnish      (Rosin      and 
Mineral  Spts.)  

59.8 

2.3 

0.9 

0.6 

63.6 

63.4 

Varnish   (Rosin,   T.   O. 
and  M.  Spts.)  
Varnish    (Rosin,   L.   O. 
and  M.  Spts.)  
B.  Damar  (100  g.)  
Varnish  (B.  Damar  and 
Mineral  Spts.)  
Drier  (Rosin,  L.  O.  and 
M.  Spts.  i&Turp.  J).. 
Varnish    (Rosin,   L.  O. 
and  Turp  ) 

40.3 
62.3 

61.1 
55.7 

2.0 
3.4 

1.6 
0.5 

0.8 
1.2 

0.5 
0.1 

0.4 
0.6 

0.0 
0.1 

43.5 

67.5 
1.2 

62.9 
63.2 

58.4 

43.5 

67.6 
0.0 

62.2 
63.4 
58.8 

Varnish  (Ros.,  L.  O.,  M. 
Spts.  |  and  Kerosene  |) 

54.3 

5.0 

2.0 

0.7 

63.0 

63.2 

177.  Loss  of  volatile  thinner  in  grinding  enamel 
pastes,  coach  and  Japan  colors.  That  a  considerable 
percentage  of  the  volatile  thinner  is  lost  through  evapo- 
ration in  grinding  pigments  in  varnishes,  Japans,  re- 
ducing oils,  etc.,  is  well  known,  but  the  full  extent  of 
this  loss  is  not  generally  appreciated.  The  actual  loss 
may  however  be  easily  determined  by  use  of  the  fol- 
lowing formula: 

X  =  Amount  of  loss  of  volatile  thinner  in  pounds. 

7  =  Number  of  gallons  of  finished  product. 

P  =  Total  weight  of  pigments  used. 

V  =  Total  weight  of  vehicle  used. 


120      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

W  =  Weight  of  volatile  thinner  present  per  gallon. 
T  =  Theoretical  yield  of  formula  in  gallons,  calcu- 
lated from  the  displacement  of  the  pigments. 
B  =  Theoretical  weight  of  paste  per  gallon. 
A  =  Actual  weight  of  paste  obtained  per  gallon, 
p      P+V 
T 


y 

T  -  x 


V  -  X 


/P+V-  AT\ 
X=W(      W-A     ) 


EXAMPLE 

Total  weight  of  pigments  used . . .  500  Ibs. 

Total  weight  of  vehicle  used 204  Ibs. 

Weight    of  volatile    thinner    per 

gallon 6.5  Ibs. 

Theoretical  weight  of  paste  calcu- 
lated from  the  displacement  of 

the  pigments 18.5  Ibs.  per  gallon 

Actual  weight  of  paste  obtained. .  21.8  Ibs.  per  gallon 

Theoretical  yield • 38  gallons 

'500  +  204  -  21.8  X  38  \ 


6.5  -  21.8  / 

x  =  -  —         —  =  52.5  Ibs.  or  7.5%  loss  by  weight. 
15. o 

en  or 

~rr-  =  8.13  gallons  loss,  or  21.39%  loss  by  volume, 
o.o 


DETERMINATION  OF  VOLATILE  THINNER         121 


178.  Loss  of  volatile  thinner  in  ageing  varnish.  In 
tanking  varnishes,  driers,  reducing  oil,  etc.,  a  slow  but 
steady  shrinkage  in  volume  takes  place,  due  to  evapo- 
ration of  the  volatile  solvent.  The  rate  at  which  this 
occurs  depends  not  only  on  the  thinner  but  the  condi- 
tions under  which  the  vehicle  in  question  is  stored. 
The  following  examples  indicate  what  may  be  expected 
under  ordinary  conditions  of  storage. 


Volatile  in 
freshly  made 
varnish 

Volatile 
3  mo. 

Volatile 
6  mo. 

Rubbing  Varnish  
Grinding  Japan 

48.0% 
55  0 

47.  1% 

46.1% 

47  0 

Gloss  Oil 

46  0 

40  0 

Damar  

47.0 

43.0 

41.0 

48  0 

46  0 

45  0 

Short  Oil  Varnish  

54.0 

50.0 

47.0 

179.  Specification  paints  and  enamels.  In  making 
paints,  enamel  and  varnish  products  under  definite 
specifications  or  to  conform  strictly  to  a  label  analy- 
sis, it  is  very  necessary  to  take  into  consideration  and 
make  due  compensation  for  losses  of  volatile  thinner 
both  in  the  grinding  and  thinning,  as  well  as  for  evapo- 
ration losses  during  the  tankage  of  the  vehicles  used. 


CHAPTER  XIV 

EXAMINATION  OF  THE  EXTRACTED   OIL 

180.  Specific  gravity.     If  the  extraction  of  the  oil 
has  been  carried  out  as  described  in  Chapter  X  with- 
out oxidation,  the  oil,  if  pure  linseed  oil,  will  come 
within  the  accepted  limits  of  specific  gravity  as  given 
in  the  chapter  devoted  to  linseed  oil,  unless  the  paint 
is  old  and  reactions  have  taken  place  between  the  pig- 
ments and  the  oil,  which  are  discussed  at  length  in 
Chapter  XV.     When  only  a  small   quantity  of  the 
oil  is  available,  a  Westphal  balance  should  be  used  in 
determining  the  gravity. 

A  low  specific  gravity  may  indicate 

(a)  Mineral  oils 

(6)  Cottonseed  oil 

(c)  Corn  oil 

(d)  Soya  bean  oil. 

A  high  specific  gravity  may  indicate 

(a)  Rosin  or  resinous  products 
(&)  Rosin  oil 

(c)  Treated  tung  oil 

(d)  Bodied  oils, — linseed,  soya  or  menhaden,  usually 
accompanied  with  considerable  percentages  of  volatile 
thinner  or  heavy  mineral  oil. 

181.  Iodine  number.     If  the  original  vehicle  con- 
tains no  volatile  thinners,  the  iodine  number,  in  con- 
nection with   the  specific   gravity,   will   indicate  the 

122 


EXAMINATION   OF  THE   EXTRACTED  OIL         123 

character    of    the    oil    present.     The    determination 
should  be  made  as  described  in  Chapter  VI. 

182.  Determination   of   the   free   fatty    acids.     Ten 
grams  of  oil  are  weighed  into  a  suitable  sized  Erlen- 
meyer  flask  and  50  c.c.  of  neutral  aldehyde-free  alco- 
hol added.     The  mixture  is  heated  to  about  60°  C. 
for  a  minute  or  two,  then  cooled  and  titrated  with 
tenth-normal  alcoholic   potash,  using  phenolphthalein 
as  an  indicator. 

Oil  made  from  moldy  seed,  or  seed  contaminated 
with  mustard  oil,  or  oil  containing  rosin  or  rosin  oil, 
will  have  a  high  acid  figure.  Pure  raw  oil  should  have 
a  low  acid  figure;  boiled  oil  will  have  a  slightly  higher 
figure.  Oils  which  have  been  in  contact  with  the 
pigment  for  a  considerable  length  of  time,  especially 
if  water  is  present,  will  show  a  very  high  acid  value. 
See  chapter  devoted  to  the  Effect  of  Storage  on  Com- 
position of  Paints. 

183.  Preparation  of  aldehyde-free  alcohol  for  alco- 
holic  potash   solution.     Dissolve   1.5   grams  of  silver 
nitrate  in  about  3  c.c.  of  water  and  add  to  a  liter 
of    alcohol    in    a    glass-stoppered    cylinder,    mixing 
thoroughly.      Dissolve    3    grams    of    pure    potassium 
hydroxide  in   10  to   15  c.c.  of  warm  alcohol.     Cool, 
pour  slowly  into  the  alcoholic  silver  nitrate  solution, 
without  shaking.     The  silver  oxide  is  precipitated  in  a 
finely   divided   condition.     Allow   to   stand  until   the 
precipitate   has    completely   settled.     Siphon   off   the 
clear  liquid  and  distill.     The  distillate  will  be  neutral 
and  free  from  aldehydes,  and  will  not  darken  when 
used  as  a  solvent  for  potash. 

184.  Free  mineral  acid.     Any  free  mineral  acid  in 
bleached  oil  is  determined  by  washing  a  definite  weight 
of  oil  with  water,  separating  the  water,  and  titrating 


124      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

the  dissolved  mineral  acid  present.  Any  mineral  acid 
found  will  usually  be  sulphuric  acid.  Its  presence  is 
decidedly  ob j  ec  tionable . 

185.  Determination   of   the    flash   point   of   linseed 
oil.     For    exact    flash-point    figures    rather    expensive 
and  complicated  testers  are  needed,  but  for  commer- 
cial tests  that  yield  approximately  the  same  figures  a 
very  simple  apparatus  may  be  used,  consisting  of  a 
two-ounce  crucible,   a  thermometer  reading  at  least 
300°  C.,  and  a  small  gas  jet  attached  to  a  rubber  tube, 
a  flame  about  the  size  of  a  pea  being  used.    The  cup 
is  filled  two-thirds  full  of  oil,  the  bulb  of  the  ther- 
mometer suspended  in  it,  and  the  oil  slowly  heated. 
The  determination  should  be  carried  on  in  a  place 
entirely  free  from  drafts.    At  short  intervals  the  gas 
flame  is  brought  close  to,  but  without  touching,  the 
surface  of  the  oil,  with  a  slow,  sweeping  motion.    The 
first  distinct  puff  of  pale-blue  flame  that  shoots  across 
the  surface  of  the  oil  indicates  the  flash  point  of  the 
oil,  and  the  temperature  at  which  this  occurs  is  noted. 

186.  Conclusions.    Hurst    states    that   linseed    oil, 
whether  raw  or  boiled,  flashes  at  about  243°  C.,  but 
this    figure    is    considerably    lower    than    those    ob- 
tained in  this  laboratory,  the  raw  oils  flashing  in  the 
vicinity  of  300°  C.  and  the  pure  boiled  oils  from  275° 
to  300°  C.    Volatile  oils  used  in  the  drier  added  to  the 
oil  lower  the  flash  point  considerably,  4  to  5  per  cent 
of  volatile  oil  lowering  the  flash  point  to  about  250°  C. 
The  other  vegetable  oils,  as  corn  and  cottonseed  oils, 
flash  at  nearly  the  same  temperature  as  linseed  oil. 
Mineral  oils,  such  as  would  be  used  for  adulteration, 
flash  at  193°  to  216°  C.,  rosin  oils  at  140°  to  167°  C. 
The  presence  of  rosin  oil  would  also  be  indicated  by  the 
strong   odor  of  rosin   given  off   during  the  heating. 


EXAMINATION  OF  THE  EXTRACTED  OIL    125 

Naphtha  and  turpentine  when  present  in  linseed  oil 
rapidly  lower  the  flash  point  according  to  the  per- 
centage present,  having  a  flash  point  themselves  but 
little  above  that  of  room  temperature. 

187.  Correction  to  be  applied  to  the  thermometer 
reading. 

Let  N  =  length  of  exposed  thread  of  mercury  ex- 
pressed in  degrees. 
T  =  observed  boiling  point. 
i  =  temperature  of  the  auxiliary  thermometer, 
the  bulb  of  which  is  midway  between  the 
ends  of  the  exposed  mercury  thread. 
0.000154  =  apparent  coefficient  of  expansion  mercury 

in  glass. 

C  =  the  correction  hi  degrees. 
Then  C  =  N(T  -  i}  +  0.000154. 

188.  Spot  test.    One  or  2  c.c.  of  the  oil  are  poured 
on  a  porcelain  plate  and  a  drop  of  concentrated  sul- 
phuric  acid   is   added   carefully.    If   pure,    the   spot 
formed  will  bear  a  marked  resemblance  to  a  begonia 
leaf.    If  rosin  or  rosin  oil  be  present,  a  black  gummy 
mass  immediately  results;   cottonseed  oil  gives  a  spot 
without  the  characteristic  markings  of  the  linseed-oil 
spot.    Mineral  oils  give  a  scum  band,  rapidly  spread- 
ing out  over  the  surface  from  the  drop,  the  margin  of 
the  band  being  uniformly  circular.    Fish  oils  give  a 
similar  reaction,  but  the  margin  of  the  band  is  not  at 
all  uniform  and  may  be  readily  distinguished  from 
mineral  oils.    With  a  little  practice  and  working  with 
oils  of  known  composition  this  test  can  be  relied  upon 
to  detect  any  appreciable  adulteration  with  the  above 
oils. 

189.  Mineral    oils.     The   spot   test   for   petroleum 
products  may  be  confirmed  by  allowing  a  sample  of 


126      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

the  oil  to  flow  down  a  sheet  of  glass  the  other  side  of 
which  has  been  painted  jet  black.  If  petroleum 
products  are  present  even  in  a  minute  quantity,  the 
sample  will  exhibit  the  "  bloom "  characteristic  of 
mineral  oils.  A  standard  sample  should  always  be 
run  for  comparison.  It  is  possible  to  remove  the 
"  bloom  "  of  mineral  oils  by  the  use  of  nitrobenzene, 
nitronaphthalene,  or  similar  compounds,  but  the 
author  is  of  the  belief  that  this  is  very  seldom  resorted 
to  in  paints,  although  it  is  frequently  done  in  liquid 
polishes  and  floor  compounds. 

190.  Quantitative  estimation  of  mineral  oil.     Quan- 
titatively the  mineral  oil  may  be  estimated  by  saponi- 
fying 10  grams  of  the  oil  with  alcoholic  potash  for  2 
hours,  using  a  return  condenser.    The  alcohol  is  dis- 
tilled off  and  the  soap  dissolved  in  75  to  100  c.c.  of 
water,  transferred  to  a  separatory  funnel,  and  50  c.c. 
of  ether  added.    The  liquids  are  then  shaken,  avoid- 
ing the  formation  of  an  emulsion  as  far  as  possible. 
The  aqueous  solution  is  then  drawn  off,  the  ethereal 
layer  washed  with  a  few  cubic  centimeters  of  water 
to  which  a  little  caustic  potash  has  been  added,  and 
poured  into  a  weighed  flask.    The  soap  solution  is 
then  returned  to  the  separator,  and  twice  extracted 
with  ether  in  the  same  way  as  before. 

The  combined  ethereal  solutions  are  distilled  off  on 
the  water  bath,  and  the  flask  dried  and  weighed.  The 
increase  in  weight  represents  the  amount  of  unsaponifi- 
able  matter,  and  unless  rosin  oil  is  present,  represents 
the  mineral  oil  with  the  exception  of  about  2  per  cent, 
the  average  amount  of  unsaponifiable  matter  in  lin- 
seed oil. 

191.  Separation  of  mineral  oil  from  rosin  oil.     The 
mineral  oil  may  be  separated  from  the  rosin  oil  in  the 


EXAMINATION  OF  THE  EXTRACTED  OIL    127 

unsaponifiable  material  by  heating  50  c.c.  of  nitric 
acid  of  1.2  specific  gravity  to  boiling  in  a  flask  of  700 
c.c.  capacity,  the  source  of  heat  removed,  and  the  un- 
saponifiable material  added.  The  flask  is  then  heated 
on  the  water  bath  with  frequent  shaking  for  about 
one-half  hour,  and  400  c.c.  of  cold  water  added.  After 
cooling,  50  c.c.  of  petroleum  ether  are  added  and  the 
flask  agitated,  the  mineral  oil  is  dissolved,  while  the 
resinous  matters  remain  in  suspension.  The  liquid  is 
then  poured  into  a  separatory  funnel,  leaving  behind 
as  much  of  the  resinous  material  as  possible.  After 
settling,  the  aqueous  liquid  is  drawn  off  and  the  ethe- 
real layer  poured  into  a  weighed  flask.  Another  por- 
tion of  petroleum  ether  is  added  to  the  rosin  remaining 
in  the  flask,  and  allowed  to  act  upon  it  for  about 
ten  minutes,  when  it  is  added  to  that  in  the  weighed 
flask.  After  distilling  off  the  ether  the  oil  is  weighed. 
Mineral  oils  lose  about  10  per  cent  when  treated  with 
nitric  acid  in  this  way,  and  hence  the  weight  .of  the 
oil  found  must  be  divided  by  0.9  in  order  to  find  the 
amount  present  in  the  sample  analyzed. 

192.  The  Outerbridge  test  for  mineral  oil  and  rosin 
oil.  A  few  drops  of  the  oil  to  be  tested  are  placed 
between  two  plates  of  clear  glass,  placed  against  a 
black  background  and  examined  by  reflected  light 
from  an  inclosed  arc  lamp,  adjusted  to  show  a  faint 
rosy  light  in  addition  to  the  powerful  white  light. 
The  presence  of  mineral  oil  is  evidenced  by  a  greenish 
fluorescence,  of  rosin  oil  by  a  bluish  fluorescence. 
Even  the  so-called  debloomed  oils  show  up  strongly 
under  this  test.  By  preparing  a  set  of  standards  of 
known  composition  as  to  percentages  of  mineral  or 
rosin  oils,  and  judging  the  sample  under  examination 
by  comparison,  reducing  it,  if  necessary,  with  a  known 


128      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

amount  of  pure  vegetable  oil  until  it  corresponds  in 
fluorescence  with  one  of  the  standards,  the  approxi- 
mate percentage  of  rosin  or  mineral  oil  may  be  deter- 
mined. For  this  purpose  50-c.c.  oil  test  bottles  may 
be  used.  The  value  of  the  test  depends  on  the  enor- 
mously intensified  fluorescence  due  to  the  particular 
source  of  light  employed. 

193.  Cottonseed  oil.     This  oil  is  seldom  found  in 
house  paints,  but  is  often  used  in  the  cheaper  class  of 
barn  paints.    The  spot  test  may  be  confirmed  by  the 
Halphen  test,  the  apparatus  required  being  a  large 
test  tube  with  a  condensing  tube  and  a  brine  bath; 
the  reagent  employed  being  a  1.5  per  cent  solution  of 
sulphur  dissolved  in  carbon  bisulphide  with  an  equal 
volume  of  amyl  alcohol  added.    Equal  volumes  of  the 
oil  and  reagent  are  heated  in  a  steam  bath  at  first, 
and,  after  the  violent  boiling  has  ceased,  in  the  brine 
bath  at  105-1 10°  C.  for  about  30  minutes.    As  little 
as  1  per  cent  of  cottonseed  oil  will  give  a  crimson  wine 
coloration.     Cottonseed  oil  heated  to  250°  C.  does  not 
respond  to  this  test. 

194.  Corn  oil.    This  oil  gives  a  spot  test  much  re- 
sembling that  given  by  linseed  oil,  but  may  be  detected 
in  linseed  oil,  if  in  quantity,  by  the  following  test: 
Dilute  with  four  volumes  of  benzine,  add  one  volume 
of  strong  nitric  acid,  shake.     Linseed  oil  turns  a  white 
color,  while  corn  oil  turns  a  reddish  orange. 

195.  Menhaden  oil.     In  addition  to  the  spot  test 
this  oil  may  be  detected  by  rubbing  a  little  of  the 
sample  vigorously  between  the  palms  of  the  hands 
or  by  heating  a  few  c.c.  in  a  porcelain  crucible.     Fish- 
oil  mixtures  give   the   characteristic    odor   of   oils  of 
this  class.    In  case  of  doubt  the  Eisenschyml  test  (see 
section  128,  Chapter  IX)  may  be  used. 


EXAMINATION  OF  THE  EXTRACTED  OIL    129 

196.  Rosin  and  rosin  oils.     These  products  are  best 
detected  qualitatively  by  means  of  the  LiebermanG- 
Storch  reaction,  which  is  of  sufficient  delicacy  to  de- 
tect  the  presence   of  even  very  small   quantities  of 
rosin  oil'  or  rosin  drier  in  boiled  oil.     Shake  1  to  2  c.c. 
of  the  oil  under  examination  in  a  test  tube  with  acetic 
anhydride   at   a   gentle  •  heat,    cool,    pipette    off    the 
anhydride,  and  place  a  few  drops  on  a  porcelain  cru- 
cible;    cover,    and   add   one   drop   of   sulphuric   acid 
(34.7  c.c.  sulphuric  acid  and  35.7  c.c.  water)  so  that 
it  will  mix  slowly.    If  rosin  or  rosin  oil  is  present  a 
characteristic   violet,   fugitive   color   results.     Certain 
fish  oils  will  give  a  very  similar  color,  but  if  present 
are  easily  detected  by  the  fishlike  odor  of  the  oil  on 
warming. 

Old  samples  of  pure  boiled  oil  give  a  color  that 
might  be  easily  mistaken  for  rosin  or  rosin  oils;  in 
such  cases  it  is  best  to  warm  the  oil  with  alcohol  so 
as  to  extract  the  bulk  of  rosin  present  and  test  the 
alcoholic  extract.  Rosin  may  be  more  completely 
separated  and  estimated  by  TwitchelPs  process  (J. 
Soc.  Chem.  Ind.,  1891,  10,  804)  or  by  Cladding's 
method  (Amer.  Chem.  J.,  3,  416).  This  process  de- 
pends upon  the  solubility  of  silver  resinate  in  ether, 
wrhile  the  silver  salts  of  fatty  acids  are  insoluble. 

197.  Soya  bean  oil.     This  oil  has  come  into  use 
quite  largely  during  the  last  few  years.     Its  chemical 
and  physical  properties  are  so  nearly  like  those  of 
linseed  oil  that  it  is  difficult  to  detect  it  with  certainty 
when  mixed  with  linseed  oil,  unless  more  than  20  per 
cent  is  present,  in  which  case  the  oil  will  be  below  the 
accepted  limits  as  to  iodine  number  and  specific  gravity. 

A  determination  of  the  oxygen  absorption  value  of 
the  oil  under  examination  frequently  gives  important 


130      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

information  as  to  its  purity.  The  rate  of  absorption 
is  much  slower  and  the  amount  of  oxygen  absorbed  is 
materially  less  in  mixtures  of  linseed  oil  with  soya, 
cottonseed  or  corn  oils.  For  this  purpose  five  very 
thin  sheets  of  aluminum,  3  in.  by  6  in.,  supported  by 
a  single  framework  of  aluminum  wire  which  separates 
the  plates  by  three-eighths  of  an  inch,  are  used.  About 
two  drops  of  oil  are  applied  evenly  over  each  sheet,  the 
total  weight  of  oil  used  being  between  0.5  and  0.7 
gram.  The  apparatus  is  suspended  under  a  shelf  to 
avoid  dust  particles  and  in  a  good  light  and  is  weighed 
daily.  This  particular  type  of  apparatus  has  been 
used  by  a  number  of  chemists,  including  the  author, 
with  very  satisfactory  results. 

198.  Reducing  oils  and  driers.  The  percentage  of 
volatile  thinner  obtained  and  the  consistency  of  the 
nonvolatile  vehicle,  taking  into  consideration  the 
character  of  the  product,  will  indicate  to  some  extent 
the  amount  of  reducing  oil  present.  Frequently  exces- 
sive quantities  of  liquid  driers  are  used  and  the  non- 
volatile portion  of  the  drier  will  disguise  to  a  large 
extent  the  character  of  the  oil  used.  If  it  becomes 
necessary  to  determine  the  amount  of  gums  or  resins 
associated  with  the  oil,  the  procedure  given  in  Chap- 
ter XIX  may  be  followed, 


CHAPTER  XV 

EFFECT  OF  STORAGE  ON  THE  COMPOSITION 
OF  PAINTS 

199.  The  changes  undergone  by  certain  types  of 
paints  on  standing  for  various  periods  have  been  in- 
vestigated by  R.   E.   Christman,   the  holder  of  the 
Acme  White  Lead  &  Color  Works,   1916,   Research 
Fellowship  at   the  University  of  Michigan,  and  are 
presented  in  brief  form  herewith.    These  or  similar 
reactions  occur  to  a  much  less  degree  in  many  varie- 
ties and  classes  of  paint  products  and,  unless  clearly 
understood,   may  easily  mislead  the  analyst,   whose 
purpose  in  making  the  analysis  is  to  correct  or  explain 
the  trouble. 

200.  Need    for    emulsifiers.    One    of    the    earliest 
difficulties  encountered  in  the  manufacture  and  use 
of  paints  was  the  tendency  of  the  heavy  pigments  to 
settle  from  the  vehicle  if  the  paint  were  permitted  to 
stand  for  a  considerable  time  before  use.    It  was  soon 
discovered,   however,   that   the   addition   of   a   small 
amount   of  water   containing  a   suitable   emulsifying 
agent  helped  to  prevent  this  settling  of  the  pigment. 
But  while  eliminating  one  source  of  difficulty,  this 
practice  has  brought  on  other  troubles. 

201.  Effect  of  Emulsifiers.     Some  emulsified  paints, 
if  allowed  to  stand  in  storage  for  a  year  or  more,  will 
show  evidence  of  deterioration  which  manifests  itself 
in  one  of  two  ways,  either  through  the  formation  of 

131 


132      PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

an  amorphous  soapy  blanket  between  the  settled  pig- 
ment and  the  supernatent  vehicle  or  by  the  gelatina- 
tion  of  the  entire  paint  to  a  mass  of  about  the  con- 
sistency of  soft  putty,  the  vehicle  seemingly  having 
disappeared  entirely.  The  first  case  is  usually  spoken 
of  as  "  skinning  "  and  the  second  as  "  puttying  "  or 
"  livering." 

Christman  found  that  this  blanket,  in  white  lead 
and  zinc  oxide  paints  with  a  small  percentage  of 
water,  contained  13  to  16  per  cent  of  lead  and  zinc 
oxides,  in  the  ratio  of  7  parts  of  zinc  oxide  to  1  part 
of  lead  oxide,  indicating  that  zinc  oxide  was  the  active 
agent.  The  oil  extracted  from  the  pigment  had  an 
apparent  free  acid  value  of  15  to  16. 

202.  Hydrolysis  of  lead  and  zinc  soaps.  Since 
these  salts  of  linseed  oil  are  easily  hydrolyzed,  it  is 
apparent  that  their  presence  in  the  dissolved  state 
would  cause  an  oil  to  show  an  acid  value  which  would 
include  the  amount  of  alkali  necessary  to  hydrolyze 
the  soaps  as  well  as  that  required  to  neutralize  the 
free  fatty  acids.  It  is  well  known  that  the  limits  of 
the  acid  number  on  a  boiled  oil  are  higher  than  those 
on  a  raw  oil,  and  the  difference  is  evidently  due  to  the 
amount  of  metallic  soap  present  as  well  as  the  increase 
in  the  true  acid  content.  The  same  difficulty  would 
be  experienced  in  attempting  to  follow  the  progress  of 
the  hardening  of  rosin  by  zinc  or  lime.  The  operator 
may  try  to  determine  the  extent  of  the  neutralization 
by  titration  with  alkali,  but  it  is  evident  that  his  re- 
sults will  show  an  acid  content  far  above  what  is 
actually  present. 

Christman  presents  the  results  obtained  with  mix- 
tures of  water  and  linseed  oil  and  various  emulsifying 
agents  and  pigments,  for  various  intervals  of  time. 


EFFECT  OF  STORAGE  ON  COMPOSITION  OF  PAINTS     133 

TABLE  XXII 

203.  Effect  of  emulsifying  agents 

No.         Emulsifying  agent  Time  Acid  Number 

1.  Linseed  oil  used 2. 98 

2.  Linseed  oil  &  water 2  h.  3. 95 

3.  Sodium  carbonate 2  h.  5. 93 

4.  "  "  ' 18  h.          22.28 

5.  "  "  22  h.  34.10 

6.  Casein 18  h.  5. 58 

7.  Chloride  of  lime 24  h.  151.70 

8.  Borax 24  h.  9.55 

9.  Zinc  oxide 18  h.  7. 38 

10.  White  lead 20  h.  7.60 

These  results  show  that  water  itself  has  a  small 
action  upon  linseed  oil,  the  action  being  increased 
through  the  emulsion.  Of  the  more  common  emul- 
sifying agents,  borax  has  the  least  effect,  the  carbo- 
nate exerts  a  marked  action,  while  the  chloride  of 
lime  is  the  most  powerful  of  all.  The  so-called  active 
pigments  are  almost  without  action. 

204.  Reaction   in   paint  on  storage.     When  ready- 
mixed  paints  are  stored,  the  first  general  reaction  is 
this  hydrolysis  of  the  oil  by  the  water  hastened  by 
the  presence  of  the  alkali.     The  pigment  itself  may 
have  some  effect  upon  the  rate,  but  its  chemical  action 
is  undoubtedly  very  small.     The  hydrolysis  is  neces- 
sarily slow  since  the  oil  and  water  are  immiscible  and 
since  some  of  the  carbonate  is  removed  by  the  zinc 
oxide.    Before  any  large  amount  of  acid  is  formed, 
the  pigment  has  settled  to  a  great  extent,  leaving  the 
clear  vehicle  above.     The  acid  and  oil  have  their  own 
kinetic  motions  and  the  acid,  coming  in  contact  with 
the  top  of  the  settled  pigment,  reacts  with  the  basic 
pigments.     The  zinc  oxide  is  the  most  basic  and  the 
most   active  and  combines  with  the  acid  with   the 
formation  of  the  zinc  soap. 


134      PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

205.  Insolubility.     The   zinc   soap   formed   on   the 
neutralization  of  the  acid -is  almost  completely  insolu- 
ble in  the  cold  vehicle  and  is  at  once  precipitated  out 
on  top  of  the  pigment.     The  white  lead  also  unites 
with  the  acid  with  the  formation  of  the  lead  soap  and 
is  carried  down  with  the  zinc,  which  builds  up  and 
forms  the  peculiar  skin  over  the  pigment.    This  re- 
action between  the  acid  and  the  pigment  takes  places 
readily,  so  that  the  oil  never  shows  a  pronounced  free 
acid  value.    This  value  was  determined  as  15-16,  and 
when  allowance  is  made  for  the  difference  due  to  the 
soaps  dissolved,  it  is  lowered  to  about  eight. 

206.  Puttied  paint.     This  designation  is  usually  ap- 
plied to  paints  in  which  the  liquid  vehicle  has  ap- 
parently disappeared,  the  entire  mass  being  of  a  solid 
or  semisolid  consistency.     The  analysis  of  such  paints 
will  usually  reveal  a  considerable  percentage  of  water 
and  of  rosin  added  either  as  gloss  oil  or  as  a  short  oil 
tung  oil-rosin  combination.     The  reactions  occurring 
in  such  paints  may  be  summarized  in  the  following 
manner.    Although  the  rosin  in  the  gloss  oil  is  usually 
limed,  there  still  remains  a  high  content  of  the  free 
rosin  acid.    This  acid  is  very  active  and  its  combina- 
tion with  basic  pigments  takes  place  in  a  very  short 
time. 

The  metallic  rosinates  formed  are  soluble  in  the 
vehicle  but  cause  it  to  become  more  viscous  and  the 
pigment  is  held  up  much  more  readily  throughout 
the  entire  paint.  On  standing,  the  water  carries  on  its 
destructive  action  on  the  oil,  and  since  the  amount 
of  water  and  alkali  are  usually  larger  in  this  class  of 
paints,  the  action  is  consequently  faster.  The  acid  of 
the  oil  is  slowly  liberated  and  comes  in  contact  with 
pigment  still  remaining  distributed  throughout  the 


EFFECT  OF  STORAGE  ON  COMPOSITION  OF  PAINTS     135 

vehicle  portion.  The  metallic  salts,  especially  the  zinc, 
are  formed,  but  due  to  the  high  viscosity  of  the 
vehicle  are  unable  to  drop  out  and  remain  suspended 
in  the  oil.  Since  the  rosin  acid  has  such  great  activity, 
there  is  very  little  free  rosin  acid  remaining,  for  this 
would  be  entirely  neutralized  before  the  oil  soaps 
really  begin  to  form.  The  vehicle  portion  becomes 
constantly  thicker  and  the  pigment  and  metallic  oil 
soaps  are  held  up  in  a  very  finely  divided  condition. 

207.  Colloidal  formation.  The  rosinate  in  the  oil 
is  probably  more  in  a  colloidal  state  than  in  a  true 
solution  and  as  the  oil  content  decreases,  due  to  the 
lesser  solubility  of  the  rosinate  in  the  volatile  thinner, 
it  tends  to  drop  out  in  the  solid  form.  When  the  con- 
tent of  the  precipitated  metallic  salts  becomes  high 
enough,  we  have  a  condition  where  the  vehicle  is  more 
in  solution  in  the  solid  constituents  than  in  suspen- 
sion in  the  liquid,  and  the  resulting  state  is  what  is 
termed  "  puttied." 

Since,  during  the  progress  of  the  reaction,  the  acids 
and  pigment  are  in  intimate  contact,  the  opportuni- 
ties for  reaction  are  much  better  and  the  oil  acids  are 
neutralized  almost  as  fast  as  liberated,  accounting  for 
the  corrected  low  free  acid  content  of  the  extracted 
oil.  As  in  the  settled  pigment  of  the  skinned  paint, 
the  tendency  is  again  to  the  formation  of  the  basic 
soaps.  But  if  the  rosin  in  the  gloss  oil  is  highly  limed 
or  for  any  similar  reason  the  pigment  should  settle 
before  the  oil  acids  become  sufficiently  large  in 
amount,  the  action  would  be  one  of  skinning  rather 
than  livering. 


136      PAINT  VEHICLES,   JAPANS   AND   VARNISHES 


TABLE  XXIII 

208.  Effect  of  storage  on  drying  oils,  extending  over  a  period  of 
eight  years l 


Specific 
Gravity 

Iodine 
Number 

Saponifica- 
tion 
Value 

Acid 
Value 

Raw  Linseed  Oil 
March,  1911  
Nov.  1914  
Sept.  1916    .  .  . 

.931 
.933 
.936 

186 
185.4 
176.9 

188 
189.6 
190.2 

2.0 

2.8 
3  3 

Feb.  1919. 

.943 

182.1 

192.3 

4  8 

Perilla  Oil 
March,  1911 

940 

180 

188 

2  0 

Nov  1914 

940 

172 

195  4 

7  4 

Sept.  1916  

.939 

193.3 

14.8 

Feb.  1919  

.941 

168.9 

192.1 

10.5 

Tung  Oil 
March,  1911  
Nov.  1914  

.944 
.946 

166 

161.5 

183 
190  3 

3.8 
5  7 

Sept.  1916  
Feb.  1919  
Soya  Oil 
March,  1911  
Nov.  1914  
Sept.  1916 

.944 
.948 

.924 
.925 
.937 

158.6 
141.1 

129 
130.2 
122  0 

188.7 
191.6 

189 
193.1 
192  1 

5.6 

6.0 

2.3 

4.7 
7  0 

Feb.  1919. 

939 

121  7 

193  4 

7  8 

TABLE  XXIV 

209.  Effect  of  storage  on  linseed  oil  with  various  pigments  after 
two  years 2 

Pigments 

Original  oil 

White  lead  (carbonate) 

Zinc  oxide 

Chrome  yellow 

Indian  red 

China  clay 

Flake  graphite 933 

Artificial  graphite 

1  Paint  Researches,  Gardner,  p.  304.     Circular  No.  60,  Paint  Mfrs. 
Association. 

2  Boughton,  J.  Ind.  &  Eng.  Chem.,  5,  282. 


Specific 
Gravity 

Iodine 
Number 

Ash 
Per  Cent 

.934 

179.6 

0.13 

.938 

177.3 

0.40 

.934 

179.7 

0.13 

.935 

175.7 

0.14 

.939 

172.5 

0.14 

.936 

171.6 

0.14 

.933 

178.2 

0.15 

.939 

180.8 

0.15 

EFFECT  OF  STORAGE  ON  COMPOSITION  OF  PAINTS    137 

210.  Iodine  number.  In  order  for  the  iodine  num- 
ber to  furnish  reliable  information  regarding  the 
nature  of  the  oil  used  in  a  paint  which  has  been  pre- 
pared or  in  storage  for  some  length  of  time,  it  is  neces- 
sary to  saponify  the  extracted  vehicle,  separate  the 
fatty  acids  and  determine  their  iodine  value,  instead 
of  determining  the  iodine  value  of  the  oil.  As  the 
iodine  value  of  the  fatty  acid  is  about  4  per  cent 
greater  than  that  of  the  glyceride,  the  minimum  limit 
according  to  Boughton  for  oil  from  North  American 
seed  should  be  about  185  and  from  South  American 
seed  178.  Due  precautions  should  be  observed  to 
prevent  oxidation  during  the  preparation  of  the  fatty 
acids,  as  described  in  Chapter  X,  Separation  of  Vehicle 
from  the  Pigment. 


CHAPTER  XVI 

ANALYSIS   OF  SOLID  AND  LIQUID   DRIERS 

211.  Materials  used.     The  paint  or  varnish  manu- 
facturer usually  prepares  his  own  driers  by  combin- 
ing the  metallic  salts  or  oxides  with  linseed  oil,  rosm, 
hard  gum  resins,  or  tung  oil,  or  combinations  of  these 
products,  giving  linoleates,   resinates,  or  tungates  as 
the  case  may  be.    The  combinations  may  be  effected 
in  either  of  two  ways,  by  fusion  or  direct  heat,  and  by 
precipitation  of  the  soaps  from  the  solutions  of  the 
corresponding  salts.     . 

The  metallic  salts  or  oxides  commonly  used  in  the 
preparation  of  driers  are: 

Litharge 
Red  lead 
Acetate  of  lead 
Oxide  of  manganese 
Borate  of  manganese 
Zinc  sulphate 
Zinc  oxide 
Cobalt  acetate 

The  majority  of  drier  manufacturers  purchase  their 
resinate  of  manganese  and  resinate  of  cobalt  instead 
of  attempting  to  effect  the  combination  themselves. 
Many  baking  blacks  also  contain  American  (Prussian) 
blue  and  various  iron  soaps  which  serve  to  increase 
the  toughness  and  degree  of  blackness. 

212.  Lead   compounds.    The  examination   of   lith- 

138 


ANALYSIS  OF   SOLID   AND   LIQUID   DRIERS        139 

arge  and  lead  acetate  offer  no  difficulties.  Red  lead 
always  contains  unconverted  litharge  and  it  is  there- 
fore advisable  to  determine  the  true  red  lead  content. 
The  author  does  not  agree  with  many  drier  manufac- 
turers that  red  lead  should  be  valued  according  to  the 
percentage  of  true  red  present  in  it.  Certain  phys- 
ical characteristics  are  even  more  desirable  than  a 
high  red  lead  content.  A  low  gravity  red  lead  (14  g. 
to  18  g.),  of  a  high  percentage  of  conversion,  is  much 
more  difficult  to  combine  with  oil  because  of  its  ten- 
dency to  "  ball  "  than  a  coarse  red  lead  (35  g.  to  40  g.) 
having  a  red  lead  content  of  60  per  cent  to  80  per 
cent,  providing  it  is  made  from  a  soft  massicot  at  a 
moderate  temperature,  and  the  drying  qualities  of  the 
resulting  product  are  fully  as  satisfactory  as  if  a  high 
conversion  red  lead  were  used. 

213.  Determination  of  true  red  lead  content.1 
Weigh  1  g.  of  finely  ground  sample  into  a  200-c.c. 
Erlenmeyer  flask,  add  a  few  drops  of  distilled  water 
and  rub  the  mixture  to  a  smooth  paste  with  a  glass 
rod  flattened  on  end.  Mix  in  a  small  beaker  30  g. 
of  c.p.  "  Tested  Purity "  crystallized  sodium  acetate, 
2.4  g.  of  c.p.  KI,  10  c.c.  of  water  and  10  c.c.  50  per 
cent  acetic  acid;  stir  until  all  is  liquid,  warming 
gently;  if  necessary  add  2  to  3  c.c.  of  water,  cool  to 
room  temperature  and  pour  into  the  flask  containing 
the  red  lead.  Rub  with  the  glass  rod  until  nearly 
all  the  red  lead  has  been  dissolved;  add  30  c.c.  of 
water  containing  5  or  6  g.  of  sodium  acetate,  and 
titrate  at  once  with  decinormal  sodium  thiosulphate, 
adding  the  latter  rather  slowly  and  keeping  the  liquid 
constantly  in  motion  by  whirling  the  flask.  When 
the  solution  has  become  light  yellow,  rub  any  undis- 

1  Am.  Soc.  for  Test.  Mat.  Stds.,  1918,  p.  651 


140      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

solved  particles  up  with  the  rod  until  free  iodine  no 
longer  forms,  wash  off  rod,  add  the  sodium-thiosul- 
phate  solution  until  pale  yellow,  add  starch  solution 
and  titrate  until  colorless,  add  decinormal  iodine 
solution  until  blue  color  is  just  restored  and  subtract 
the  amount  used  from  the  volume  of  sodium  thiosul- 
phate  that  had  been  added. 

214.  Calculation.    The  iodine  value  of  the  sodium- 
thiosulphate   solution  multiplied  by  0.94193  =  PbO2; 
the  iodine  value  multiplied  by  2.69973  =  Pb304;    the 
Pb02  value  multiplied  by  2.86616  =  Pb304. 

The  sodium-thiosulphate  solution  and  the  starch 
solution  shall  be  prepared  as  follows: 

215.  Sodium-thiosulphate      solution      (decinormal). 
Dissolve  24.83  g.  of  c.p.  sodium  thiosulphate,  freshly 
pulverized  and  dried  between  filter  paper,  and  dilute 
with  water  to  1  liter  at  the  temperature  at  which  the 
titrations  are  to  be  made.    The  solution  is  best  made 
with  well-boiled  water  free  from  C02,  or  let  stand  8 
to   14  days  before  standardizing.     Standardize  with 
pure,    resublimed   iodine,    as  described  in  Treadwell- 
Hall,  "Analytical  Chemistry,"  Vol.  II,  p.  602  (1910), 
and   also   against   pure   potassium   iodate;     the   two 
methods  of  standardization  should  agree  within  0.1 
per  cent  on  iodine  value. 

216.  Starch  solution.     Stir  up  2  to  3  g.  of  potato 
starch  with  100  c.c.  of  1  per  cent  salicylic-acid  solu- 
tion, and  boil  the  mixture  till  starch  is  practically 
dissolved,  then  dilute  to  1  liter,  or  as  per  Lord.1 

If  sample  contains  an  appreciable  amount  of  nitrite 
(nitrate  has  no  effect  on  method),  leach  out  water- 
soluble  matter,  dry  residue  and  determine  Pb02  as 
above,  calculating  to  basis  of  original  sample. 

217.  Oxide    of    mangajiese.     The    fineness    of    the 
1  Notes  on  Metallurgical  Analysis,  page  103  (1903). 


ANALYSIS   OF   SOLID  AND   LIQUID   DRIERS        141 

particles  is  an  important  factor  in  determining  the 
suitability  of  this  product  for  use  in  driers  and  var- 
nishes. Numerous  practical  tests  made  by  the  author 
show  that  there  is  only  a  slight  difference  between 
particles  that  pass  a  200-mesh  screen  and  those  that 
pass  a  300-mesh  screen,  in  the  total  percentage  of 
manganese  that  will  combine  with  the  oil  during  a 
normal  cook.  The  residue  that  remains  on  a  200- 
mesh  screen,  however,  enters  into  combination  much 
more  slowly  and  incompletely  and  this  residue  should 
be  kept  to  as  low  a  percentage  as  possible. 

218.  Procedure.     The   manganese   content   is   best 
determined  by  the  ferrous  sulphate  method.1 

Ferrous  sulphate  solution.  Carefully  dissolve  90  g. 
ferrous  sulphate  in  200  c.c.  sulphuric  acid  (1.84)  and 
900  c.c.  distilled  water.  Standardize  against  the  po- 
tassium permanganate  solution  each  time  before  using. 

Potassium  permanganate  solution.  Dissolve  10  g. 
potassium  permanganate  solution  in  distilled  water 
and  make  up  to  1000  c.c.,  allow  to  stand  overnight 
or  preferably  several  days.  Standardize  against  fer- 
rous ammonium  sulphate  or  sodium  oxalate. 

219.  Determination.     Weigh  0.5  g.  into  a  250-c.c. 
Erlenmeyer  flask,  add  50  c.c.  standard  ferrous  sul- 
phate solution,  cover  with  watch  glass  and  heat  to 
boiling  until  solution  of  the  manganese  is  effected. 
Dilute  to  about  150  c.c.  and  titrate  with  the  stan- 
dard permanganate  solution  in  the  usual  manner. 

220.  Resinate   of   manganese.     The  percentage  of 
manganese   in   this   product   varies   greatly.    In   the 
precipitated    variety    the    best    grades    will    contain 
approximately    7    per    cent    manganese.     The    fused 
variety  runs  much  lower  owing  to  the  fact  that  when 

1  Barneby,  J.  Ind.  and  Eng.  Chem.  9,  9C1  (1917). 


142      PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

the  maximum  amount  of  manganese  is  used,  the  prod- 
uct will  contain  considerable  insoluble  material  and 
be  very  black  in  color.  It  should,  however,  contain 
not  less  than  1.75  per  cent  manganese. 

221.  Procedure.    The  manganese   content   can  be 
determined  by  incinerating  a  weighed  quantity  of  the 
resinate   in   a   large   crucible.    Extract   with   boiling 
water  to  remove  soluble  salts,  decant  through  a  filter 
paper,  then  incinerate  the  paper  hi  the  same  crucible. 
Moisten  the  ash  with  a  few  drops  of  nitric  acid  to  oxi- 
dize any  reduced  oxide,  heat  to  expel  the  acid,  dissolve 
with  a  measured  quantity  of  the  standard  ferrous  sul- 
phate   solution    and    titrate    with    permanganate    as 
described  under  Oxide  of  Manganese. 

222.  Borate    of    manganese.     The    composition    of 
manganese  borate  is  more  or  less  a  matter  of  dis- 
pute, because  of  the  fact  that  when  the  precipitated 
borate  is  washed,  it  continually  loses  boric  acid.    It 
can  therefore  be  washed  in  the  press  to  a  very  slight 
extent    only   as   the   dried   product    otherwise   turns 
brown,  owing  to  the  separation  of  manganese  oxides. 
The  best  commercial  grades  have  a  manganese  con- 
tent of  about  18  per  cent.    The  author  has  examined 
samples  containing  as  low  as  10  per  cent.    As  the 
value  of  manganese  borate  hi  a  varnish  is  due  essen- 
tially to  the  manganese  content,  it  is  advisable  that 
an  accurate  method  of  analysis  should  be  selected. 

223.  Procedure.    Heckel l   made   an   extended   in- 
vestigation of  the  methods  in  use,  including  the  bis- 
muthate,   Ford,  and  Ford  Williams  methods.    With 
certain  essential  modifications,  he  found  the  last  to 
be  the  most  accurate  and  suitable  for  the  examination 
of  manganese  borates.    The  author  has  found   this 

1  Drugs,  Oils  and  Paints,  Aug.  1918,  page  80. 


ANALYSIS   OF   SOLID  AND  LIQUID  DRIERS       143 

method  with  additional  cautions  very  satisfactory, 
not  only  for  manganese  borates  but  with  complex 
drier  mixtures.  This  determination  is  made  as  de- 
scribed beginning  with  section  230.  A  1-gram  sample 
is  used  and  dissolved  in  the  one-third  nitric  acid. 

224.  Cobalt  resinate.     The  variety  commonly  used 
is  the  fused,  the  best  grades  of  which  contain  about 
2    per    cent    of    cobalt.    The   preferable    method    of 
analysis  is  to  dissolve  the  ash  in  hydrochloric  acid, 
precipitate  with  nitrite   of  potash,  filter,  wash  thor- 
oughly, dissolve  in  sulphuric  acid  and  evaporate  until 
fumes    appear,    then    make   alkaline   with   ammonia 
and  deposit  the  cobalt  by  electrolysis.     If  the  neces- 
sary apparatus  is  not  available  the  following  method 
will  give  satisfactory  results. 

225.  Procedure.    Incinerate  a  weighed  quantity  of 
the  resinate,   igniting  the  ash  thoroughly,   cool  and 
weigh.    Dissolve  in  hydrochloric  acid,  adding  a  small 
quantity  of  water  and  filter.    Add  5  c.c.  sulphuric 
acid  to  filtrate  and  evaporate  to  dryness  in  a  porcelain 
evaporating  dish  and  weigh  as  sulphate,  the  sulphate 
being  stable  at  moderate  temperatures.    If  desired,  the 
sulphuric  acid  solution  after  running  down  to  fumes  to 
remove  the  hydrochloric  acid  may  be  neutralized  with 
ammonia  and  the  cobalt  precipitated  as  CoNKtPCX  as 
described  in  section  241. 

226.  Determination  of  the  metallic  driers  that  may 
be  present  in  varnishes,  liquid  driers,  and  vehicle  mix- 
tures.    Due  to  the  fact  that  paint  or  enamel  vehicles, 
driers  and  varnishes  are  frequently  blends  of  two  or 
more  very  different  products,  it  is  not  unusual  for  the 
analyst  to  be  confronted  with  a  mixture  containing 
lead,  copper,  or  iron  as  impurities  from  the  varnish 
kettle,   or  iron  from  iron  linoleates  or  other  soaps, 


144      PAINT^  VEHICLES,   JAPANS  AND  VARNISHES 

manganese,  cobalt,  and  calcium,  and  occasionally 
zinc,  e.g.,  a  mixing  varnish  containing  lead  and  man- 
ganese may  be  mixed  with  another  varnish  containing 
cobalt  and  limed  rosin  (calcium  rosinate)  in  order  to 
meet  certain  requisites  as  to  color,  toughness,  gloss, 
body  working  qualities  and  service  value. 

The  prevailing  practice  of  incinerating  the  drier  and 
determining  the  lead  and  manganese  in  the  ash  will 
give  results  that  are  too  low  on  the  lead  content,  as 
from  5  to  15  per  cent  of  the  lead  is  lost  when  burning 
at  a  low  red  heat. 

The  following  procedure  avoids  any  loss  from  the 
volatilization  of  the  lead,  and  under  favorable  condi- 
tions the  decomposition  can  be  completed  in  3  hours 
and  is  equally  suitable  for  lead  and  manganese  only, 
or  for  complex  mixtures. 

227.  Analytical  procedure.  In  order  to  secure  suffi- 
cient quantities  of  the  metallic  compounds  to  render 
the  analytical  procedure  reasonably  accurate,  it  is 
advisable  to  take  two  samples  of  approximately  20 
grams  each,  which  are  weighed  into  600-c.c.  beakers, 
the  volatile  thinners  driven  off  as  rapidly  as  possible, 
100  c.c.  concentrated  sulphuric  acid  added  and  heated 
gently  at  first  to  avoid  excessive  frothing,  then  heated 
vigorously  with  frequent  stirring  until  almost  all  of 
the  gum  and  oil  have  been  oxidized  with  reduction  of 
the  acid  to  sulphur  dioxide.  The  black  solution  is 
allowed  to  cool  somewhat  and  65  per  cent  perchloric 
acid  added  in  small  portions,  5  c.c.  to  20  c.c.  in  all. 
After  heating  about  30  minutes  longer,  the  solution 
should  entirely  clear  up  and  is  then  evaporated  to  a 
bulk  of  3  c.c.  to  5  c.c.,  diluted  with  water  and  the  lead 
sulphate  filtered  off  on  to  a  porcelain  Gooch  crucible, 
carefully  reserving  the  filtrate. 


ANALYSIS   OF  SOLID   AND   LIQUID   DRIERS        145 

In  most  cases,  if  the  sulphuric  solution  is  evaporated 
to  dry  ness,  the  residue  chars  and  to  remove  every 
trace  of  organic  matter,  it  must  again  be  boiled  with 
sulphuric  acid  and  25  c.c.  potassium  or  ammonium 
perchlorate  added  and  again  evaporated  to  remove 
most  of  the  sulphuric  acid.  Sometimes  it  may  be 
necessary  to  evaporate  practically  to  fusion  of  the 
bisulphate  formed.  This  last  trace  of  organic  matter 
does  not  seem  to  interfere  in  any  way  with  the  deter- 
mination of  tha  lead,  the  only  requisite  being  that 
the  brown  color  of  the  solution  due  to  organic  matter 
shall  completely  disappear. 

228.  Lead.  The  lead  sulphate  is  redissolved  in  a 
suitable  quantity  of  ammonium  acetate  solution, 
filtered,  neutralized  with  ammonia  and  made  just 
barely  add  to  litmus  with  dilute  hydrochloric  acid 
(1  to  10),  dilute  to  about  350  c.c.  A  comparatively 
small  quantity  of  free  acid  will  prevent  some  of  the 
lead  from  precipitating.  Precipitate  the  lead  with 
hydrogen  sulphiie.  Settle,  filter,  and  wash  with  cold 
water. 

If  calcium  is  to  be  estimated,  10  c.c.  to  15  c.c.  of 
sulphuric  acid  are  added  to  the  filtrate  from  the  lead 
sulphide  in  an  evaporating  dish,  heated  over  a  fairly 
hot  flame  until  all  of  the  acetic  acid  and  almost  all  of 
the  ammonium  sulphate  have  been  driven  off.  Cool, 
redissolve  in  sufficient  water  and  add  to  the  filtrate 
from  the  copper  sulphide,  section  229. 

Place  filter  and  lead  sulphide  precipitate  in  25  c.c. 
of  nitric  acid  and  25  c.c.  of  water,  heat  gently  until 
the  lead  has  all  dissolved,  as  shown  by  the  residual 
sulphur  having  a  yellow  to  whitish  color.  Do  not 
boil  hard  enough  thoroughly  to  disintegrate  the  filter 
paper.  If  difficulty  is  experienced  in  dissolving  the 


146      PAINT   VEHICLES,   JAPANS   AND   VARNISHES 

lead  contained  in  the  sulphur  particles,  it  is  better  to 
collect  them  into  a  ball  with  the  aid  of  a  stirring  rod 
and  remove  to  a  small  beaker  and  treat  with  a  few 
cubic  centimeters  of  concentrated  nitric  acid,  and  heat 
until  dissolved,  then  pour  back  into  the  larger  beaker. 
Pour  solution  and  filter  paper  on  to  a  suction  funnel 
provided  with  a  platinum  cone.  If  any  fine  particles 
pass  through,  pour  the  filtrate  back  again.  This 
procedure  permits  the  washing  of  the  filter  mass  with 
a  very  small  amount  of  water,  thus  saving  considerable 
time  in  the  subsequent  evaporation.  Add  5  c.c.  of 
dilute  sulphuric  acid  to  filtrate,  and  evaporate  until 
sulphur  trioxide  fumes  appear.  Cool,  add  25  c.c.  of 
water,  25  c.c.  of  alcohol;  allow  to  stand  one-half 
hour  with  occasional  stirring;  filter,  using  Gooch 
crucible,  wash  with  dilute  alcohol,  dry,  heat  gently 
over  ordinary  lamp,  and  weigh  as  lead  sulphate. 

229.  Copper.     If  a  highly  acid  gum  has  been  used, 
appreciable  traces  of  copper  will  be  found  present  and 
constitute  an  impurity  which  need  not  be  estimated 
but  must  be  removed. 

The  filtrate  from  the  original  lead  sulphate  (section 
227)  is  treated  with  hydrogen  sulphide  and  filtered  to 
remove  any  copper  sulphide  formed.  The  concen- 
tration of  sulphuric  acid  should  be  about  5  per  cent 
during  the  precipitation.  This  filtrate  is  combined 
with  the  filtrate  from  the  lead  sulphide  (section  228), 
which  may  contain  a  portion  of  the  calcium,  and  the 
combined  filtrate  boiled  until  all  traces  of  hydrogen 
sulphide  have  disappeared,  the  removal  of  which  can 
be  assisted  with  the  addition  of  a  few  drops  of  bro- 
mine water. 

230.  Manganese.     The    above    solution    is    evapo- 
rated nearly  to  dryness  in  a  porcelain  evaporating  dish. 


ANALYSIS   OF   SOLID  AND   LIQUID   DRIERS       147 

Dissolve  in  30-40  c.c.  ^  colorless  nitric  acid,  allowing 
sufficient  time  for  any  calcium  to  go  into  solution. 
If  a  large  quantity  of  calcium  is  present,  the  amount 
of  dilute  nitric  acid  must  be  increased  accordingly. 
Filter  off  the  insoluble  if  any.  Pour  into  a  250-c.c. 
graduated  flask  and  make  up  to  the  mark  with  dis- 
tilled water.  Shake  until  the  contents  of  the  flask 
are  thoroughly  mixed  and  pipette  out  a  100-c.c.  aliquot 
portion. 

231.  Precipitation    of    manganese.     Place    this   ali- 
quot in  a  400-c.c.  beaker,  add  50  c.c.  of  1-1  colorless 
nitric  acid;   heat  to  boiling,  then  add  cautiously  three 
grams  of  solid  sodium  or  potassium  chlorate.     The 
solution  is  now  boiled  for  fifteen  minutes  or  until  it  is 
thought  that  all  of  the  manganese  has  been  precipi- 
tated as  manganese  dioxide.     Three  grams  more  of 
sodium  or  potassium  chlorate  and  15  c.c.  more  1-1 
nitric  acid  are  added  to  the  solution,  and  then  the 
solution  is  boiled  down  to  a  total  volume  of  about 
one-third   or   one-fourth   of   the    original   volume   in 
order  to  make  certain  that  all  of  the  manganese  has 
been  precipitated.     Sodium  chlorate  is  preferable  to 
the  potassium  salt  as  it  is  easier  to  wash  out.    A  color- 
less nitric  acid  must  be  used,  otherwise  some  of  the 
manganese  dioxide  is  reduced  and  dissolved. 

If  a  purple  color  forms  here,  it  is  an  indication  that 
some  permanganic  acid  is  being  formed  and  the  solu- 
tion should  be  boiled  until  this  color  disappears. 

232.  Filtration   of   precipitate.     A  filter  meanwhile 
has  been  prepared  by  placing  in  the  neck  of  an  ordi- 
nary 60°  long-stemmed  funnel,  enough  glass  wool  to 
fill  the  funnel  proper  about  one-third  full.     The  glass 
wool  is  tucked  in  the  funnel  tightly  with  the  finger 
and  then  covered  with  a  good  dense  layer  of  asbestos 


148      PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

fiber,  the  asbestos  being  placed  on  the  glass  wool  by 
pouring  through  the  funnel  a  thick  emulsion  of  finely 
divided  asbestos  fiber. 

The  manganese  precipitate  in  the  beaker  is  allowed 
to  stand  for  a  few  minutes  until  fairly  cool,  and  is  then 
filtered  through  the  glass  wool  and  asbestos.  Great 
care  must  be  exercised  in  order  to  prevent  a  suspen- 
sion of  finely  divided  manganese  precipitate  from 
creeping  over  the  top  of  the  asbestos  and  glass  wool 
filter  and  running  through  into  the  filtrate. 

233.  Washing.     One  other  difficulty  which  must  be 
guarded  against  is  the   tendency  of  the  manganese 
dioxide   to   run   through   in   a   colloidal   state.     This 
tendency  is  increased  by  washing  the  precipitate  with 
boiling  water,  and  it  should  therefore  be  washed  care- 
fully with  small  portions  of  warm,  not  hot,   water. 
If  the  precipitate  runs  through  in  a  colloidal  form,  the 
manganese  may  be  reprecipitated  by  placing  the  fil- 
trate containing  the  manganese  on  the  hot  plate,  add- 
ing a  large  excess   (4-5  grams)   of  additional  potas- 
sium or  sodium   chlorate  and  20-30   c.c.   1-1   nitric 
acid  and  boiling  until  the  colloid  coagulates  and  the 
manganese  is  reprecipitated. 

The  precipitate  in  the  funnel  is  next  washed  with 
hot  water  containing  a  little  nitric  acid  and  finally 
with  hot  distilled  water  until  the  filtrate  is  free  from 
acid.  As  stated  above,  care  and  judgment  must  be  used 
in  washing  the  precipitate  on  the  filter,  because  too 
much  washing,  especially  with  boiling  water,  seems  to 
produce  a  tendency  for  the  precipitate  to  become  col- 
loidal and  run  through. 

234.  Solution   of   precipitate.     The   precipitate   to- 
gether  with   the   glass   wool   asbestos   mass   is   next 
removed  from  the  funnel  and  replaced  in  the  beaker 


ANALYSIS  OF  SOLID  AND  LIQUID   DRIERS       149 

in  which  the  original  precipitation  was  made;  a  solu- 
tion of  ferrous  sulphate  of  known  strength  is  run 
down  the  sides  of  the  funnel  to  remove  the  last  traces 
of  manganese  dioxide,  the  funnel  during  this  opera- 
tion draining  into  the  beaker  containing  the  precipi- 
tate. The  funnel  is  washed  out  with  distilled  water 
and  an  excess  of  standard  ferrous  sulphate  solution  is 
then  run  on  to  the  precipitate  in  the  beaker  from  the 
same  burette  used  in  washing  down  the  funnel. 

The  asbestos  mass  is  stirred  and  agitated  with  a 
number  of  small  pieces  of  small-diameter  glass  rods 
during  the  addition  of  the  ferrous  sulphate  solution. 
If  difficulty  is  experienced  in  entirely  dissolving  the 
manganese  precipitate,  it  must  be  manipulated  with 
a  glass  rod  until  the  glass  wool-asbestos  mass  is  prac- 
tically white  in  color  and  shows  no  black  particles  hi  it. 

235.  Titration.     The  solution  of  the  precipitate  in 
the  excess  of  ferrous  sulphate  is  then  titrated  with  a 
solution    of   potassium   permanganate,    until   a   pink 
color  is  produced  not  disappearing  under  2  or  3  minutes. 
Read  the  burette  and  deduct  the  amount  used  from 
that  to  which  the  amount  of  ferrous  sulphate  taken 
would  have  been  equivalent;  the  difference  is  equiv- 
alent to  the  Mn  present  in  the  precipitate.    This,  cor- 
rected by  the  factor  for  the  permanganate  solution, 
will  give  the  amount  of  Mn  in  milligrams. 

The  preparation  of  the  standard  solutions,  the  re- 
actions involved  and  the  calculations  required  are 
very  clearly  stated  in  the  following  excerpt  from  Lord 
and  Demorest's  Metallurgical  Analysis  under  the  Ford- 
Williams  method. 

236.  Preparation    of    the    permanganate    solution. 
Dissolve  1.151  grams  of  pure  KMn04  in  water  and 
dilute  to  1  liter.     One  cubic  centimeter  of  this  solu- 


150      PAINT   VEHICLES,   JAPANS  AND   VARNISHES 

tion  will  have  the  same  oxidizing  power  as  0.001  gram 
of  manganese  in  the  form  of  the  brown  precipitate 
(Mn02).  Check  the  solution  against  pure  iron  or 
pure  ammonium  ferrous  sulphate  (NH4)2Fe(SO4)26H20. 
Dissolve  0.1425  gram  of  the  salt  in  50  c.c.  of  water 
containing  2  c.c.  of  H2S04.  This  should  consume  just 
10  c.c.  of  the  permanganate  solution.  Run  in  the  solu- 
tion until  the  last  drop  gives  a  permanent  pink  color. 

If  more  or  less  than  10  c.c.  is  required,  calculate 
the  amount  of  Mn  to  which  each  cubic  centimeter  of 
the  permanganate  is  equivalent  by  the  proportion, 
0.001:  x  =  n:  10,  n  being  the  number  of  cubic  centi- 
meters of  solution  used  in  the  test,  and  x  the  required 
value. 

237.  Preparation  of  the  ferrous  sulphate  solution. 
Dissolve  20.18  grams  of  pure  crystallized  ferrous  sul- 
phate (FeS047H20)  in  about  500  c.c.  of  water,  to  which 
25  c.c.  of  concentrated  H2S04  have  been  added,  and 
then  dilute  to  1  liter. 

Determine  its  strength  against  the  permanganate 
solution  by  measuring  15  c.c.  with  a  pipette  into  a 
beaker,  adding  about  25  c.c.  of  water  and  1  c.c.  of 
H2S04  and  then  running  in  the  permanganate  till  the 
pink  color  is  permanent.  About  30  c.c.  should  be 
required.  This  value  must  be  determined  frequently, 
as  the  solution  of  ferrous  sulphate  alters  rapidly  from 
the  oxidizing  action  of  the  ah-.  In  large  amounts  it 
is  best  kept  in  a  carboy  and  covered  with  a  layer  of 
kerosene  oil  to  keep  out  air.  The  solution  can  be  pre- 
served in  this  way  for  some  time  with  but  little  altera- 
tion, and  can  be  drawn  out  by  a  siphon  as  needed. 

238.  Calculations.     From  the  two  formulas  already 
given  we  have  the  relations  between  the  Mn02,  FeS04 
and  KMnO4  as  follows: 


ANALYSIS  OF   SOLID  AND  LIQUID   DRIERS       151 

One  atom  of  Mn  in  the  form  of  brown  precipitate 
(Mn04)  will  oxidize  two  atoms  of  Fe  as  ferrous  sul- 
phate. Two  molecules  of  permanganate  will  oxidize 
ten  atoms  of  Fe  as  ferrous  sulphate,  that  is  to  say,  two 
molecules  of  permanganate  will  oxidize  the  same 
amount  of  iron  as  will  five  molecules  of  Mn02  con- 
taining five  atoms  of  manganese.  Therefore,  to  find 
how  much  KMn04  will  be  needed  to  have  the  sama 
oxidizing  power  as  0.001  gram  of  Mn  in  the  form  of 
the  brown  precipitate  we  have  the  proportion: 

5  atoms  Mn:  2  mol.  KMn04  =  275:  316.3  =  0.001:  x, 
which  gives  x  =  0.00115  gram,  the  amount  of  KMn04 
to  be  dissolved  hi  1  c.c.  if  1  c.c.  is  to  be  equivalent  to. 
0.001  gram  Mn  as  "  brown  precipitate."  This  is  1.151 
grams  hi  a  liter. 

To  determine  the  amount  of  iron  or  of  ammonium 
ferrous  sulphate  to  which  1  c.c.  is  equivalent,  we  have: 

1  atom  Mn:  2  atoms  Fe  =  55: 112  =  0.001:  a,  in 
which  x  is  the  required  amount  of  iron.  The  value 
of  x  is  0.002034.  To  determine  the  amount  of  the 
ammonium  ferrous  sulphate,  as  this  contains  one- 
seventh  of  its  weight  of  iron,  multiply  the  value  of 
x  by  7  =  0.01425  for  1  c.c.,  or  the  figure  given  in  the 
directions  for  10  c.c. 

That  15  c.c.  of  the  ferrous  sulfate  solution  may  be 
equivalent  to  30  c.c.  of  the  permanganate  it  must  con- 
tain 0.06102  Fe.  This  corresponds  to  20.18  grams  of 
FeS04,  7H20  to  the  liter. 

The  filtrate  from  the  manganese  precipitate  should 
be  reserved  for  estimation  of  iron,  if  present,  and 
cobalt. 

239.  Iron.  In  black  baking  Japans,  iron  linoleate 
or  other  iron  soaps  are  generally  present  in  consider- 
able quantity.  Driers  cooked  in  an  iron  kettle  usually 


152      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

contain  appreciable  traces  of  iron  and  it  is  therefore 
advisable  to  recognize  the  possibility  of  its  presence 
and  provide  for  its  elimination  and,  if  desired,  its 
estimation. 

To  the  filtrate  from  the  oxide  of  manganese  pre- 
cipitate are  added  5  grams  ammonium  chloride,  and  the 
solution  is  made  barely  alkaline  with  ammonia  and 
filtered  boiling  hot.  If  a  considerable  precipitate  of 
ferric  hydroxide  is  obtained  it  may  contain  a  small 
amount  of  the  cobalt  and  calcium.  It  should  there- 
fore be  redissolved  in  hydrochloric  acid,  again  pre- 
cipitated with  ammonia  and  the  filtrate  added  to  the 
first  filtrate  from  the  ferric  hydroxide. 

If  the  percentage  of  iron  is  desired,  the  ferric  hy- 
droxide precipitate  is  dissolved  in  hydrochloric  acid, 
sulphuric  acid  added,  run  down  to  fumes,  diluted  with 
water,  reduced  with  an  aluminum  spiral  or  metallic 
zinc  and  titrated  with  permanganate  in  the  usual 
manner. 

240.  Cobalt.    The  filtrate  from  the  ferric  hydroxide 
precipitation  will  contain  any  cobalt  present,  calcium 
from  the  limed  rosin  and  occasionally  zinc,  which  is 
sometimes  used  for  hardening  rosin  instead  of  lime. 
If  zinc  is  suspected  of  being  present  it  may  be  sepa- 
rated by  the  Zimmerman1  method.     Otherwise  the 
filtrate  from  the  ferric  hydroxide  is  made  distinctly 
alkaline  with  ammonia  and  treated  with  hydrogen 
sulphide,  the  black  cobaltous  sulphide  filtered  off  and 
the  filtrate  reserved  for  the  estimation  of  calcium  if 
desired. 

241.  Precipitation.     The  cobaltous  sulphide  is  dis- 
solved in  nitric  acid,  5  c.c.  sulphuric  acid  added  run 
down  to  fumes  to  remove  all  traces  of  hydrochloric 

1  Treadwell  &  Hall,  Analytical  Chemistry,  p.  158,  4th  ed. 


ANALYSIS  OF  SOLID  AND  LIQUID   DRIERS       153 

acid.  Cool,  add  25  c.c.  water  and  ammonium  hy- 
droxide until  only  very  faintly  acid,  otherwise  all  of 
the  cobalt  will  not  precipitate.  In  other  words,  the 
solution  should  be  practically  neutral.  Add  10  times 
the  weight  (estimated)  of  the  cobalt,  of  dry  hydrogen 
ammonium  phosphate,  heat  to  almost  boiling  and 
hold  at  that  temperature  for  10  minutes.  Cool,  filter 
on  to  a  weighed  porcelain  Gooch  crucible,  washing 
with  a  hot  1  per  cent  solution  of  hydrogen  ammonium 
phosphate  and  finally  with  dilute  alcohol.  Dry  at 
100°  C.  to  105°  C.  and  weigh  as  CoNIL^PCX. 

242.  Calcium.  The  nitrate  from  the  cobaltous  sul- 
phide is  boiled  thoroughly  and  the  calcium  precipi- 
tated in  the  usual  manner  with  ammonium  oxalate 
and  estimated  gravimetrically  or  volumetrically  as 
desired. 


CHAPTER  XVII 

COMPARATIVE  ANALYSIS  OF  BLACK  BAKING  JAPANS 

243.  The  author  will  not  attempt  to  formulate  an 
analytical  procedure  for  the  examination  of  air  drying 
Japans  and  the  various  bituminous  coatings  for  damp 
proofing  stone,  masonry,  and  concrete  surfaces,  as  the 
ingredients  that  may  be  present  are  almost  numberless 
and  are  difficult  to  identify  when  present  hi  complex 
mixtures,  as  is  frequently  the  case. 

244.  Method.    The  author  does  not  believe  that  it 
is  feasible  to  develop  a  purely  analytical  procedure 
that  will  differentiate  the  various  constituents,  together 
with   the   percentages    thereof,    of   a   baking   Japan. 
However,  if  the  analyst  is  familiar  with  the  raw  ma- 
terials used,  he  can  develop  a  method  partly  analyti- 
cal and  partly  constructive  that  will  enable  him  to 
arrive    at    an    equivalent    composition    within    very 
definite  limits.    A  procedure  suited  to  the  require- 
ments of  one  chemist  may  fail  with  another,  or  it  may 
fail  due  to  the  presence  of  a  new  or  unusual  com- 
ponent.   The  working  basis  of  the  method  herewith 
given  as  applied  to  baking  Japans  illustrates  how  the 
problem  may  be  attacked  and  the  manner  of  procedure 
developed  as  the  analyst  proceeds. 

245.  Separation  of  the  volatile  portion.     Kerosene 
is  usually  present,  therefore  distillation  by  direct  heat 
or  with  superheated  steam  introduces  a  serious  error, 
as   the   temperature   required   to   remove   the   heavy 
volatile  fractions  is  sufficiently  high  to  cause  an  appre- 
ciable amount  of  the  asphaltum  hydrocarbons  and  of 

154 


ANALYSIS  OF   BLACK   BAKING  JAPANS 


155 


the  fatty  acid  compounds  of  the  stearine  pitches  to 
pass  over  with  the  petroleum  thinners. 

Distillation  by  boiling  with  water  at  100°  C.  will 
not  remove  all  of  the  volatile  thinner  without  special 
precautions  being  adopted,  as  the  viscous,  gummy 
nature  of  the  nonvolatile  retains  within  itself  the  last 
portion  of  the  thinner.  To  overcome  this  difficulty 
the  following  scheme  may  be  adopted. 

246.  Procedure.  A  weighed  amount  (100  grams  to 
130  grams)  of  the  Japan,  together  with  400  c.c.  water, 
are  placed  in  a  1-quart  varnish  can.  A  distilling  bulb 
and  overflow  burette  are  used  as  described  in  Chap- 
ter XIII.  The  distillation  is  continued  as  long  as 
any  appreciable  quantity  of  volatile  thinner  is  ob- 
tained, the  aquous  distillate  being  returned  to  the  dis- 
tilling can  as  needed. 

TABLE  XXV 

Amount  taken,  126  grams 
TYPICAL  DISTILLATION  OF  VOLATILE  THINNER 


No.  of  Fraction 


Aqueous  distillate 


1  

250 

2  
3  

.  ..  200 
.  ..  200 
.  ..  200 

5 

...  200 

6 

...  200 

7 

..  200 

8 

200 

9 

..  200 

10  

....  200 

11  

....  200 

Total.  . 

...  2250  c.c. 

Volatile  thinner 
c.c. 
90.2 
4.1 
2.1 
1.6 
1.5 
1.1 
0.8 
0.6 
0.6 
0.4 
0.2 
103. 2  c.c. 


247.  Solution.  The  surplus  water  is  removed  from 
the  distilling  can,  the  last  traces  being  driven  off  by 
a  gentle  heat,  and  the  residue  put  into  solution  under 
a  reflux  condenser  with  100  c.c.  of  pentane  (Standard 
Oil  Co.) ,  using  the  fraction  distilling  between  50°  C. 
to  60°  C.,  and  reserving  the  remaining  portion  from 


156      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

which  the  100-c.c.  fraction  is  obtained,  for  subsequent 
addition.  The  pentane  used  should  be  a  redistilled 
product,  fractions  above  60°  C.  being  eliminated.  A 
specially  redistilled  petroleum  spirits  can  be  used  if 
the  pentane  is  not  available. 

248.  Precipitation.     After  solution,,  remove  the  con- 
tents of  the  can  to  an  800-c.c.  beaker,  add  with  con- 
stant stirring  sufficient  pentane,  including  the  amount 
used  and  the  portion  reserved,  to  make  a  total  of 
600  c.c.  pentane  used.    For  complete  removal  from 
the  can,  it  is  advisable  to  cut  the  can  open  and  wash 
out  with   a  brush.     Allow  to   stand   1   hour  at  10° 
to  15°  C.    The  bulk  of  the  asphaltum  and  other  gums 
present  will  be  precipitated,  leaving  all  of  the  oil  in 
solution  except  a  small  percentage  which  is  in  com- 
bination with  the  lead  and  manganese.     The  precipi- 
tated gums  are  given  two  washings  of  50  c.c.  each  of 
cold  pentane,  removed  to  a  filter,  dried  and  weighed. 
The  precipitated  gums  are  designated  as  the  "break" 
and  are  discussed  subsequently  under  the  heading  of 
Estimation  of  Gums. 

249.  Distillation.     The  pentane  is  distilled  off  from 
the  liquid  portion  at  a  gentle  heat  on  the  electric  hot 
plate,   400   c.c.   of  water  added  and  the  distillation 
continued  as  previously  described,  to  remove  the  last 
of   the   heavy  naphtha  and  kerosene.     This  volatile 
thinner  is  added  to  that  obtained  in  the  first  distillation. 

EXAMPLE:    126  grams  taken,  treated  as  previously 
described. 


No.  of  Fra 

12. 
13. 
14. 
15. 
16. 
C 

cti 
01] 

sn 
ibine 

d  totals 

Aqueous  distillate 
c.c. 

200 
200 
200 
200 
200 
3250  c.c. 

Volatile  thinner 
c.c. 

0.8 
0.6 
0.4 
0.2 
0.1 
105.  3  c.c. 

ANALYSIS  OF  BLACK  BAKING  JAPANS  157 

The  water  is  completely  removed  from  the  oil  and 
soluble  gum  residue,  due  precautions  being  observed 
to  prevent  oxidation  as  described  in  Chapter  XIX. 
This  residue  is  weighed  and  treated  as  described  under 
Estimation  of  Oil. 

250.  Analysis  of  the  volatile  portion.     After  deter- 
mining the  gravity  of  the  volatile  thinner  it  should  be 
distilled   in   an   Engler   flask,    electrically   heated   as 
described  in  Chapter  II,  and  the  distillation  figures 
and  solvent  strength  compared  with  those  of  the  dif- 
ferent petroleum  thinners  available.     From  this  com- 
parison a   mixture  can  be  calculated  which  will  ap- 
proximate the  distillation   desired.    This  is   checked 
by  a  trial  distillation  and  further  revision  made  as 
may  be  found  necessary,  as  the  working  qualities  of  a 
Japan  depend  very  materially  on  the  rate  of  evapora- 
tion and  solvent  strength  of  the  thinners  used. 

251.  ^Sulphonation  test.     Frequently  coal  tar  naph- 
thas or  oils  may  be  present,  especially  if  the  Japan 
hi  question  is  a  very  dense  black,  indicative  of  the 
presence  of  bone  pitch,   which  is  difficultly  soluble 
when    in    considerable    percentage    with    a    straight 
petroleum   thinner.    This   test  is   conducted   on   the 
recovered   volatile    thinner    as    described    hi    Chap- 
ter XIII.    It  should  be  remembered  that  the  natural 
asphaltic  constituents  of  petroleum  thinner  react  in 
the  same  way  with  aromatic  hydrocarbons,  as  shown 
in  the  following  table: 

TABLE  XXVI 
TYPICAL  SULPHONATION  TESTS 

Percentage  of  Reacting 
Product  Hydrocarbons 

P.  &  V.  M.  naphtha 8.0  per  cent 

Mineral  spirits 12. 5    " 

Heavy  mineral  spirits 12. 0   " 

Kerosene 15.0    " 

Min.  spts.  90%  coal  tar  naphtha  10% 22.5    " 

Volatile  thinners  from  Japan 14. 5   " 


158      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

From  the  above  table  it  is  apparent  that  the  re- 
covered volatile  thinner  in  question  is  free  from  coal 
tar  naphthas  or  other  volatile  coal  tar  products. 

252.  Estimation    of    gums.     The    author    has    not 
found  a  method  which  will  precipitate  all  of  the  gums 
that  presumably  may  be  present,  without  precipitat- 
ing a  portion  of  the  heat-treated  oils,  and  as  an  alter- 
native has  adopted  the  scheme  previously  described 
of  precipitating  as  much  of  the  gum  as  can  be  safely 
accomplished,  without  precipitating  the  oil. 

The  classes  of  gums,  so  called,  that  may  be  present 
are: 

1.  Asphaltums,  of  which  gilsonite  is  most  widely 
used. 

2.  Bone  pitches,  used  especially  because  of  their 
intense  blackness. 

3.  Stearine  pitches  of  varying  degrees  of  consistency 
and  blackness. 

4.  Petroleum  pitches,  varying  in  consistency  from 
solid  to  semi-liquid.    They  are  used  chiefly  in  low- 
priced  blacks,  acid-resisting  products,  etc.,  and  are  not 
suitable  for  use  in  the  medium  and  higher  priced 
blacks  such  as  usually  reach  the  analyst,  unless  they 
have  received   special   treatment,    of  which   blowing 
with  air  under  heat  is  the  most  common. 

5.  Varnish  gums.    The  various  resins  used  in  the 
manufacture  of  the  transparent  varnishes  are  some- 
times used  hi  baking  Japans  to  increase  the  gloss. 
Such  use,  however,  is  not  generally  looked  upon  with 
favor  because  of  their  tendency  to  make  the  coating 
brittle. 

253.  Characteristics.     The  various  asphaltums,  ste- 
arine  pitches,  and  bone  pitches  to  be  found   on   the 
market  differ  greatly  in  their  characteristics,  but  those 


ANALYSIS  OF  BLACK  BAKING  JAPANS  159 

which  can  be  used  successfully  in  baking  Japans  fall 
within  certain  well-defined  limits  which  eliminate  a 
large  number  of  these  products  as  probable  constit- 
uents. They  must  respond  readily  to  treatment  in 
the  varnish  kettle,  must  be  freely  soluble  in  the  pe- 
troleum thinners  used  and  of  as  high  a  degree  of 
blackness  as  it  is  possible  to  obtain,  consistent  with 
the  foregoing  requirements.  This  for  instance  elimi- 
nates the  soft  asphalts,  also  the  difficultly  soluble 
asphalts  such  as  elaterite  and  similar  products.  The 
requirements  as  to  blackness  and  toughness,  as  well 
as  complete  solubility  in  the  finished  and  cooled  Japan, 
eliminate  many  of  the  stearine  pitches. 

The  genuine  asphaltums  have  a  brown  to  brownish 
black  "  streak,"  a  fixed  carbon  content  of  15  per  cent 
to  20  per  cent,  and  are  entirely  unsaponifiable.  The 
bone  pitches  are  intensely  black,  have  a  fixed  carbon 
content  of  20  per  cent  to  25  per  cent  and  are  only 
slightly  soluble  in  petroleum  thinners,  a  considerable 
percentage  of  oil  or  coal  tar  thinner  being  required  to 
keep  them  in  solution  in  a  Japan.  They  usually  con- 
tain from  a  trace  to  15  per  cent  of  saponifiable  matter. 
The  desirable  stearine  pitches  are  fairly  black  in  color, 
have  a  fixed  carbon  content  of  5  per  cent  up  to  occa- 
sionally 10  per  cent  and  have  a  considerable  percent- 
age of  saponifiable  matter,  occasionally  as  high  as  65 
per  cent.  In  admixtures  the  stearine  pitch  "  break  " 
imparts  a  certain  degree  of  softness  or  approach  to  a 
rubber-like  consistency  according  to  the  percentage 
present. 

Blown  petroleum  residuums  and  pitches  offer  more 
serious  difficulties,  as  they  constitute  a  wide  range  of 
products  of  somewhat  diverse  characteristics.  They 
are  all  unsaponifiable,  and  the  more  solid  products  re- 


160      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

main  largely  with  the  break  while  the  more  liquid 
residuums  remain  in  the  pentane  soluble  portion  and 
are  distinguished  from  the  soluble  stearine  pitch  by 
being  neutral  and  having  a  very  low  iodine  value, 
whereas  the  soluble  stearine  pitch  has  a  considerable 
acid  value,  a  considerably  higher  iodine  value  and  is 
partially  saponifiable. 

The  fossil  resins  will  remain  almost  wholly  and 
rosin  only  partially  with  the  "  break."  Their  detec- 
tion and  estimation  will  be  discussed  in  a  subsequent 
paragraph. 

254.  Comparative  tests.  It  is  therefore  necessary 
for  the  analyst  to  prepare  a  series  of  black  Japans 
containing  one  gum  only  and  also  typical  admixtures. 
These  blacks  should  be  prepared  in  the  usual  manner 
except  that  they  do  not  contain  the  volatile  thinner. 
The  percentage  of  "  break,"  the  "  streak  "  or  blackness 
of  the  "  break "  when  rubbed  out  on  a  sheet  of  un- 
glazed  white  paper  or  porcelain,  the  hardness,  and 
the  percentage  of  fixed  carbon  of  each  should  be  care- 
fully determined.  From  the  data  thus  obtained  it  is 
a  comparatively  easy  matter  to  fuse  together  weighed 
amounts  of  the  individual  breaks  and  test  the  result- 
ing mass  for  blackness,  consistency,  and  fixed  carbon 
content,  repeating  the  procedure  until  a  product  is 
obtained  that  corresponds  to  the  sample  under 
examination. 

It  should  be  remembered  that  whereas  only  about 
70  per  cent  of  the  asphaltum  and  of  the  stearine  pitch 
is  precipitated  by  the  pentane,  90  per  cent  or  better 
of  the  bone  pitch  is  precipitated,  but  when  in  admix- 
ture with  considerable  percentages  of  linseed  oil  and 
stearine  pitch  it  becomes  somewhat  more  soluble  and 
only  about  80  per  cent  breaks  out.  Iron  and  man- 


ANALYSIS  OF   BLACK   BAKING  JAPANS  161 

ganese  linoleates  present  in  the  Japan  as  driers  affect 
the  consistency  of  the  "  break,"  making  it  less  friable. 
The  quantity  however  is  usually  quite  small  and  can 
be  calculated  from  the  percentage  of  iron  and  man- 
ganese found  in  the  ash  from  incinerating  the  "  break  " 
after  deducting  the  amount  of  iron  normally  present 
in  "  break  "  of  the  gums  used. 

255.  Fixed  carbon.  Occasionally  a  heavily  oxidized 
oil  may  be  present  and  be  precipitated  with  the  gum 
break,  giving  it  a  somewhat  rubber-like  consistency 
and  a  lower  fixed  carbon  value.  If  there  is  reason  to 
suspect  the  presence  of  such  oil  and  also  if  fossil  gums 
or  rosin  be  suspected,  the  break  may  be  saponified, 
the  unsaponifiable  removed  with  benzol  and  the  oil 
acids  and  the  gum  acids  in  the  aqueous  solution  sepa- 
rated and  estimated  by  esterification  as  described  in 
Chapter  XIX,  Analysis  of  Varnish  and  Enamel  Liquids. 

The  following  table  gives  the  fixed  carbon  content 
of  representative  gums  and  other  products  as  deter- 
mined by  the  author. 

TABLE  XXVII 
TYPICAL  ANALYSES 

r,     ,     .  Fixed  Carbon 

Product  Per  Cent 

Stearine  pitch,  natural 6.6 

"  "      after  a  normal  cook 8.0 

"      break..  .     8.3 


Gilsonite,  natural 


break. 


Bone  pitch,  natural 

"        "      break 

Heat-treated  linseed  oil 

"Break"  from  baking  Japan 

Duplicate  "break"  of  same  blackness  and  consist- 
ency obtained  by  melting  together  the  compo- 
nent breaks 14. 1 


17.0 
18.4 
21.0 
24.0 
0.6 
14.6 


256.    Calculation.     Having  ascertained  the  percent- 
ages of   component  breaks  which,  when   melted   to- 


162      PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

gether,  give  the  closest  approximation  to  that  obtained 
from  the  Japan  under  examination,  as  to  blackness, 
consistency,  and  fixed  carbon  content,  and  also  having 
established  the  extent  to  which  each  of  these  cooked 
gums  will  be  precipitated  by  the  pentane  treatment, 
the  total  percentage  of  gums  present  in  the  Japan 
may  be  readily  calculated. 


EXAMPLE 

Percentage  of  "break"  or  insoluble  gums  23.8 
cent. 

Percentages    of   component  "breaks"  required   to 
duplicate 

54  per  cent  stearine  pitch  having  a  break  coefficient  of  70 

38  "      "    gilsonite  "      "       "          "          "69 

8  "      "    bone  pitch          "      "       "          "  "  «n 

Calculated  "  break  "  coefficient  =  70  approximate; 

(23.8  -=-  70)100  =  34  per  cent  total  gum  content; 

34  -  23.8  =  10.2  per  cent  soluble  gums. 


per 


Product 

Ratio  of 
Gums  in 
Break 

Break  Co- 
efficient 

Calc.  Ratio 
of  Gums  in 
Japan 

Percentage 
on  Basis  of 
Total  Gum 
Content 

Stearine  pitch  .... 

54 

70 

77 

54 

Asphaltum  

38 

69 

55 

39 

Bone  pitch  

8 

80 

10 

7 

The  accuracy  of  the  above  calculations  is  checked 
against  the  analysis  of  the  portion  reserved  for  the 
estimation  of  oil,  i.e.,  the  pentane  soluble  residue  from 
the  "break."  If  a  serious  discrepancy  is  found  to 
exist,  petroleum  pitch  or  other  uncommon  components 
or  an  unusual  manufacturing  practice  may  be  sus- 


ANALYSIS  OF  BLACK   BAKING  JAPANS  163 

pected  and  the  procedure  will  have  to  be  developed 
accordingly.  Unless  the  petroleum  residuum  or  pitch 
is  of  an  unusual  nature  its  presence  and  an  approxi- 
mate idea  of  the  amount  present  may  be  ascertained 
by  determining  the  percentage  of  saturated  hydro- 
carbons and  of  free  asphaltous  acids  in  the  break  as 
described  by  Abraham  in  his  treatise  on  Asphalts  and 
Allied  Substances,  page  298,  and  comparing  the  results 
obtained  with  those  from  Japans  of  known  composi- 
tion containing  such  petroleum  products  as  the  base. 

Occasionally  a  crude  coal  tar  distillate  may  have 
been  used  as  one  of  the  solvents,  especially  if  a  bone 
pitch  is  present.  Not  all  of  this  product  will  be  re- 
moved by  the  steam  distillation  and  this  fact  must 
be  taken  into  consideration  when  testing  for  the  pos- 
sible presence  of  coal  tar  pitches  by  the  well-known 
diazo  and  anthraquinone  reactions.1 

257.  Estimation  of  oil.  Five  grams  of  the  oil  and 
pentane  soluble  gum  residue,  obtained  as  previously 
described,  are  saponified  in  the  usual  manner  and  the 
percentage  of  unsaponifiable  determined.  It  is  pref- 
erable to  use  benzol  instead  of  ether  as  the  extracting 
agent.  If  an  emulsion  forms  that  refuses  to  break, 
add  more  benzol  to  a  total  of  about  500  c.c.  and  then 
100  c.c.  of  ethyl  alcohol,  and  allow  to  stand  in  a  warm 
place  overnight. 

The  percentages  of  saponifiable  in  the  pentane 
soluble  part  of  representative  cooked  stearine  pitches 
are  established.  Therefore  the  percentage  of  un- 
saponifiable plus  the  calculated  percentage  of  saponi- 
fiable due  to  the  stearine  pitch  present  subtracted 
from  the  total  of  the  oil  and  soluble  gum  residue 
gives  the  approximate  percentage  of  oil  present.  To 

1  Abraham,  Asphalts  and  Allied  Substances,  pages  549-550. 


164      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

this  percentage  should  be  added  the  small  percentage 
of  oil  combined  with  the  manganese  and  iron  in  the 
"  break "  portion  as  previously  discussed.  The  acid 
soaps  in  the  aqueous  solution  may  be  recovered  and 
after  liberation  of  the  free  acid  may  be  esterified  for 
the  separation  of  any  rosin  or  resin  not  precipitated 
by  the  pentane  treatment.  The  acid  value  and  Lie- 
bermann-Storch  reaction  of  the  recovered  gum  acids 
indicate  their  source. 

258.  Acid  Value.    Heat  5  grams  of  the  soluble  por- 
tion with  50  c.c.  of  alcohol  on  the  steam  bath  for  30 
minutes  under  an  air  condenser  with  frequent  shaking. 
Decant  from  the  insoluble  residue  while  hot  and  ex- 
tract the  residue  twice  more  with  alcohol  in  the  same 
manner.     Combine  the  3  extracts,  cool,  add  10  c.c. 
of  a  nearly  saturated  barium  chloride  solution,  use 
phenolphthalein    as    the    indicator    and    titrate   with 
tenth-normal    aqueous   potash.    A   blank   should   be 
run  on  the  alcohol.    A  high  acid  value  may  indicate 
stearine  pitch  in  quantity,  or  a  low  grade  of  fish  oil, 
samples  of  which  have  been  examined  by  the  author 
with  acid  values  as  high  as  60,  whereas  the  acid  value 
of  the  linseed  oil  developed  in  the  cooking  of  the 
Japan  seldom  exceeds  20. 

259.  Iodine   value.    The  iodine  values  of  the  oil 
and  soluble  gum  portion,  of  the  unsaponifiable  obtained 
therefrom  and  of  the  fatty  acids  obtained  from  the 
saponifiable  throw  considerable  light  on  the  probable 
composition,     especially    when    compared    with    the 
values   obtained   from   heat-treated    oils,   their   fatty 
acids  and  the  iodine  values  of  the  saponifiable  and  un- 
saponifiable portions  of  representative  cooked  pitches. 

260.  Oils  used.     Formerly  linseed  oil  was  the  only 
oil  used  in  baking  Japans;    at  the  present  time  fish 


ANALYSIS  OF  BLACK  BAKING  JAPANS  165 

oils,  chiefly  menhaden,  soya-bean  oil,  perilla  oil,  and 
occasionally  a  small  percentage  of  tung  oil,  as  well  as 
linseed  oil  are  being  used.  Inasmuch  as  the  heat 
treatment  they  receive  varies  with  the  requirements  of 
the  Japan  and  also  according  to  the  ideas  of  the  var- 
nish maker,  it  is  impossible  to  identify  the  oils  used 
by  analysis.  In  the  absence  of  stearine  pitch  a  rough 
approximation  may  be  arrived  at  by  the  constants  of 
the  recovered  fatty  acids. 

261.  Fixed  carbon  value  of  oil  portion.  The  com- 
position of  the  oil  and  soluble  gum  portion  is  further 
confirmed  by  determining  its  fixed  carbon  value  and 
comparing  with  the  fixed  carbon  value  of  the  pentane 
soluble  parts  of  cooked  oils,  asphaltums  and  stearine 
pitches,  a  few  typical  values  being  given  in  accom- 
panying table. 

TABLE  XXVIII 
TYPICAL  FIXED  CARBON  VALUES 

Product 


Asphaltum,  soluble  .............................  14.  0 

Stearine  pitch,  soluble  ..........................  1.2 

Treated  linseed  oil  .............................  0.6 

Oil  portion  from  baking  Japan  ...................  3.5 

262.  Estimation  of  metallic  driers.  The  iron  and 
manganese  are  determined  hi  the  usual  manner  from 
a  suitable  quantity  of  ash  obtained  by  incinerating  a 
weighed  quantity  of  the  Japan.  Frequently  the  ash 
is  so  light  that  the  air  currents  from  the  flame  used 
will  carry  away  an  appreciable  amount.  This  can  be 
avoided  by  cooling  the  crucible  and  moistening  the 
ash  with  a  few  drops  of  water  and  then  reheating. 
From  the  total  quantity  of  iron  obtained  must  be  de- 
ducted the  amount  normally  present  in  the  gums 
used,  which  is  quite  appreciable.  The  corrected  per- 
centage of  iron  and  the  manganese  are  calculated  to 


166      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

the  corresponding  linoleates.  The  author  knows  of  no 
way  of  determining  whether  the  iron  obtained  is 
derived  from  Prussian  blue  or  from  a  prepared  iron 
soap  which  is  the  more  recent  practice.  If  lead  is 
present  it  is  best  estimated  as  in  the  preceding  chapter, 
using  sulphuric  and  perchloric  acids. 

263.  Conclusion.  In  order  to  obtain  concordant 
results,  the  analytical  procedure  as  to  quantities,  con- 
centration, temperatures,  etc.,  must  be  kept  strictly 
comparative  as  regards  the  sample  under  examination 
and  in  establishing  the  necessary  data  from  products 
of  known  composition.  In  order  to  properly  interpret 
the  results  obtained  the  analyst  must  have  a  broad, 
comprehensive  knowledge  of  the  raw  materials  used 
and  the  prevailing  manufacturing  practice. 


CHAPTER  XVIII 

ANALYSIS   OF   SHELLAC   AND   LACQUERS 

264.  Valuation.     The     analytical     examination     of 
shellac   and   shellac   varnishes   has  been   carried   out 
much  more  extensively  in  recent  years,  owing  to  the 
improved  chemical  methods  available  for  determining 
adulteration.     The  value  of  commercial  shellac  is  de- 
pendent upon  several  conditions,  chiefly  its  color,  its  free- 
dom from  dirt,  as  well  as  its  content  of  added  rosin,  and 
in  the  case  of  bleached  shellac,  the  moisture  content 
and   its    ready    solubility    in    alcohol.    With    shellac 
varnish,  the  kind  and  proof  of  the  solvent  used,  the 
percentage  of  rosin  or  other  substitutes  if  any,  and 
the  percentage  of  shellac  present  are  the  determining 
factors  in  its  valuation. 

265.  Determination  of  the  body  of  shellac  varnishes. 
Three  to  five  grams  of  the  well-stirred  sample  are  weighed 
into  a  weighed  flat-bottom  Petri  dish  and  evaporated 
to  a  constant  weight  in  the  steam  oven.    The  result 
is  calculated  in  pounds  per  gallon.    If  a  platinum 
evaporating  dish  be  used  and  the  evaporation  con- 
ducted over  a  water  bath,  the  amount  taken  should 
not  be  over  1  gram.     Taking  the  weight  of  a  gallon 
of  alcohol  at  60°  F.  as  6.75  pounds,  the  pounds  per 
gallon  may  be  ascertained  by  means  of  the  following 
table: 


167 


168      PAINT   VEHICLES,   JAPANS  AND   VARNISHES 


TABLE  XXIX 

Per  Cent  Pounds 

Residue  Per  Gallon 

30.77 3.0 

34.15 3.5 

37.20 4.0 

40.00 4.5 

42.55 5.0 

44.90..  ..  5.5 


47.06 

49.05 

50. 91 

52.63 

54.23.. 


.  6.0 
.  6.5 
.  7.0 
.  7.5 
.  8.0 


266.  Examination    of    the    solvent.     One    hundred 
grams  of  the  varnish  are  carefully  distilled  at  a  mod- 
erate temperature,  using  an  oil  bath  and  a  distilling 
bulb  of  the  type  described  in  Chapter  XIII,  collecting 
the  distillate  in  a  cooled  flask  with  as  little  exposure 
to  the  air  as  possible.    The  proof  of  the  solvent  is 
determined  from  its  gravity.    If  the  solvent  is  re- 
covered from  a  bleached  shellac  varnish  its  proof  will 
be  somewhat  lower  than  when  originally  used,  due  to 
the  residual  water  in  the  bleached  shellac. 

267.  Detection    of    rosin  —  Liebermann-Storch    re- 
action.   About  1  gram  of  the  sample  is  dissolved  in 
about   15   c.c.   of  acetic   anhydride,   warming  gently 
until  the  solution  is  complete.     Cool  thoroughly  under 
the  tap.    The  rosin  will  remain  in  solution  while  the 
greater  part  of  the  shellac  will  separate  out.    Filter. 
Place  a  few  drops  of  the  filtrate  on  a  porcelain  crucible, 
cover,  and  add  by  means  of  stirring  rod  one  drop  of 
sulphuric  acid  (34.7  c.c.  sulphuric  acid  and  35.7  c.c. 
water)  so  that  it  will  mix  slowly.     If  rosin  is  present 
a  characteristic  violet  fugitive  color  results.    A  pure 
shellac  should  give  no  coloration. 

According  to  Hicks  l  this  reaction  is  not  very  sen- 

1  Eighth  International  Congress  of  Applied  Chemistry,  Vol.  XII, 
p.  115. 


ANALYSIS  OF  SHELLAC  AND  LACQUERS    169 

sitive,  its  limit  for  rosin  in  shellac  being  about  2  per 
cent,  that  is  to  say,  shellacs  yielding  Wijs  iodine 
values  below  22-24  may  not  give  a  positive  reaction 
when  this  test  is  applied.  He  recommends  the  Hal- 
phen  test  as  much  more  sensitive  and  reliable.1 

268.  Halphen  test.  The  Halphen  reagent  consists 
of  two  solutions:  (a)  1  part  by  volume  of  phenol  dis- 
solved in  2  parts  of  carbon  tetrachloride  and  (6)  1 
part  by  volume  of  bromine  in  4  parts  of  carbon 
tetrachloride. 

The  procedure  which  was  found  most  convenient  for 
conducting  the  test  is  as  follows:  A  small  quantity 
of  the  powdered  resin,  or  the  residue  resulting  from  the 
evaporation  of  the  ethereal  extract  of  a  larger  quantity 
of  the  substance  to  be  investigated,  is  dissolved  in 
from  1  to  2  c.c.  of  solution  A.  This  solution  is  poured 
into  one  of  the  cavities  of  an  ordinary  porcelain  color- 
reaction  plate  until  it  just  fills  the  depression;  a  por- 
tion of  the  solution  will  soon  be  seen  to  spread  out  on 
the  flat  part  of  the  plate  a  short  distance  beyond  the 
rim  of  the  cavity,  unless  too  much  of  the  carbon 
tetrachloride  has  been  lost  through  evaporation  dur- 
ing the  process  of  solution,  when  a  drop  or  two  more 
should  be  added  to  produce  the  spreading  effect  above 
referred  to.  Then  immediately  in  an  adjacent  cavity 
of  the  plate  a  c.c.  or  so  of  solution  B  is  placed  and 
the  bromine  vapors  evolved  are  allowed  to  impinge 
upon  the  surface  of  the  solution  in  the  other  cavity. 
Sometimes  it  is  necessary  to  blow  a  gentle  current  of 
ah*  in  the  proper  direction  to  accomplish  this  satis- 
factorily, or  both  cavities  may  be  covered  by  a  watch 
crystal  of  suitable  size. 

The  color  reactions  begin  almost  immediately  with 
1  Hicks,  J.  Ind.  and  Eng.  Chem.,  Vol.  3,  No.  2  (1911). 


170      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

the  contact  of  the  bromine  vapors  and  are  best  ob- 
served upon  the  flat  portion  of  the  test-plate.  In 
most  cases  they  last  long  enough  for  satisfactory  obser- 
vation; the  changes  hi  colors  are  practically  over, 
however,  in  a  period  varying  from  five  to  ten  minutes. 
The  author  has  found  this  method  very  satisfactory 
where  rosin  was  the  only  adulterant;  where  the  rosin 
is  in  admixture  with  other  gums,  as  may  be  the  case 
in  the  various  substitutes  now  offered  to  the  trade, 
this  method  has  not  proven  satisfactory. 

269.  Preparation  of  sample  for  estimation  of  rosin. 
If  much  rosin  is  present,  it  is  not  safe  to  take  the 
residue  after  evaporation  for  the  quantitative  estima- 
tion as  has  been  shown  by  Langmuir.     "  A  little  rosin 
(iodine  value  224.3)  was  dissolved  in  alcohol,  evapo- 
rated on  the  water  bath  and  heated  5  hours.    It  then 
showed   a  value   of   148.2.    Similarly,   a   dark  rosin 
175.5  fell  to  131." 

A  quantity  of  the  varnish  sufficient  to  yield  0.2  to 
0.4  gram  of  residue  is  weighed  from  a  small  vial,  pro- 
vided with  a  perforated  stopper  carrying  a  shortened 
1  c.c.  pipette,  into  a  200-c.c.  Erlenmeyer  flask;  the 
weight  of  the  sample  used  being  thus  obtained  by 
difference.  The  sample  in  the  flask  is  carefully  evapo- 
rated at  a  low  temperature  until  very  pasty  and  then 
dissolved  in  the  requisite  amount  of  acetic  acid  and 
chloroform  and  the  iodine  number  then  determined  as 
described  in  the  following  sections.  The  error  due  to 
the  action  of  the  small  amount  of  alcohol  remaining 
in  the  pasty  mass  on  the  thiosulphate  is  negligible. 

270.  Determination  of  rosin  in  shellac  as  prescribed 
by    American    Society   for   Testing    Materials.1     Solu- 
tions  required.     The   solutions   required   are   one   of 

i  A.  S.  T.  M.  Standards,  1918,  page  610. 


ANALYSIS  OF   SHELLAC  AND   LACQUERS          171 

iodine  monochloride  containing  13  g.  of  iodine  per 
liter,  in  glacial  acetic  acid  that  has  a  melting  point  of 
14.7  to  15°C.  and  is  free  from  reducing  impurities; 
and  another  of  sodium  thiosulphate,  made  by  dissolving 
24.83  g.  of  the  pure  salt  hi  a  liter  of  water.  In  addi- 
tion to  these  solutions  there  is  required  a  quantity  of 
acetic  acid  of  the  same  strength  as  that  used  for  mak- 
ing the  solution  of  iodine  monochloride.  Pure  chloro- 
form and  starch  are  also  necessary. 

271.  Iodine  monochloride.     The  preparation  of  the 
iodine-monochloride  solution  presents  no  great  diffi- 
culty, but  it  shall  be  done  with  care  and  accuracy  in 
order  to  obtain  satisfactory  results.     There  shall  be 
in  the  solution  no  sensible  excess  either  of  iodine  or 
more  particularly  of  chlorine,  over  that  required  to 
form  the  monochloride.    This  condition  is  most  satis- 
factorily attained  by  dissolving  in  the  whole  of  the 
acetic  acid  to  be  used  the  requisite  quantity  of  iodine, 
using  a  gentle  heat  to  assist  the  solution,  if  it  is  found 
necessary.    Set  aside  a  small  portion  of  this  solution, 
while  pure,  and  pass  dry  chlorine  into  the  remainder 
until  the  halogen   content  of  the  whole  solution  is 
doubled.     Ordinarily  it  will  be  found  that  by  passing 
the  chlorine  into  the  main  part  of  the  solution  until 
the  characteristic  color  of  free  iodine  has  just  been 
discharged,  there  will  be  a  slight  excess  of  chlorine, 
which  is  corrected  by  the  addition  of  the  requisite 
amount   of   the  unchlorinated  portion  until   all  free 
chlorine  has  been  destroyed.    A  slight  excess  of  iodine 
does  little  or  no  harm,  but  excess  of  chlorine  must  be 
avoided. 

272.  Method.     Introduce  0.2  g.  of  ground  shellac 
into  a  250-c.c.  dry  bottle  of  clear  glass  with  a  ground- 
glass  stopper,  add  20  c.c.  of  glacial  acetic  acid  (melt- 


172      PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

ing  point  14.7  to  15°  C.)  and  warm  the  mixture  gently 
until  solution  is  complete  (except  for  the  wax).  A 
pure  shellac  is  rather  difficultly  soluble;  solution  is 
quicker  according  to  the  proportion  of  rosin  present. 
Add  10  c.c.  of  chloroform  and  cool  the  solution  to  21 
to  24°  C.  The  temperature  should  be  held  well  within 
these  limits  during  the  test.  Add  20  c.c.  of  Wijs 
solution  from  a  pipette  having  a  rather  small  delivery 
aperture.  Close  the  bottle,  place  in  a  dark  place, 
and  note  the  time.  It  is  convenient  to  keep  the 
bottles  during  the  test  partly  immersed  in  water  which 
should  be  kept  as  nearly  as  possible  between  22  and 
23°  C. 

Pure  shellac  will  scarcely  alter  the  color  of  the 
Wijs  solution.  If  in  small  amount,  rosin  will  produce 
a  slowly  appearing  red-brown  color.  In  large  amount, 
rosin  causes  an  immediate  coloration,  increasing  in 
intensity  as  time  passes.  After  1  hour,  add  10  c.c. 
of  10  per  cent  potassium-iodide  water  solution. 
Titrate  the  solution  immediately  with  the  sodium- 
thiosulphate  solution;  25  or  30  c.c.  may  be  run  in  imme- 
diately, unless  the  shellac  is  very  impure,  and  the  re- 
mainder gradually,  with  vigorous  shaking.  Just  before 
the  end,  add  a  little  starch  solution.  The  end  point 
is  sharp,  as  the  reaction  products  of  shellac  remain 
dissolved  in  the  chloroform;  any  color  returning  after 
half  a  minute  or  so  is  disregarded. 

273.  Blank.  A  blank  determination  should  be  run 
with  20  c.c.  of  Wijs  solution,  20  c.c.  of  acetic  acid, 
10  c.c.  of  chloroform,  and  10  c.c.  of  10  per  cent  potas- 
sium-iodide solution.  The  blank  is  necessary  on  ac- 
count of  the  well-known  effect  of  temperature  changes 
on  the  volume,  and  possible  loss  of  strength  of  the 
Wijs  solution. 


ANALYSIS  OF  SHELLAC  AND   LACQUERS  173 

274.  Adulterated  samples.     In  the  case  of  grossly 
adulterated  samples,  or  in  the  testing  of  pure  rosin, 
it  is  necessary  to  use,  instead  of  0.2  g.  of  material,  a 
smaller  amount,  say  0.15  g.  or  even  0.1  g.,  in  order 
that  the  excess  of  iodine  monochloride  may  not  be 
too  greatly  reduced,  since  the  excess  of  halogen  is  one 
of  the  factors  in  determining  the  amount  of  absorp- 
tion.   In  case  less  than  25  c.c.  of  the  thiosulphate  solu- 
tion are  required,  another  test  should  be  made,  using 
a  smaller  amount  of  the  shellac  to  be  tested. 

275.  Weighing.     In    weighing    shellac,    some    diffi- 
culty is  at  times  experienced  on  account  of  its  electrical 
properties.     In  very  dry  weather  it  may  be  found  that 
the  necessary  handling  to  prepare  it  for  weighing  has 
electrified  it,  and  that  it  may  be  necessary  to  leave  it 
on  the  balance  pan  at  rest  for  a  few  minutes  before 
taking  the  final  weight. 

276.  Calculation.     No  pure  shellacs  show  a  higher 
iodine  absorption  than  18.     As  shellac  is  relatively  a 
high-priced  material  and  as  the  variation  between  its 
highest  and  lowest  figure  is  not  great,  it  is  recom- 
mended  that    18   should   be   taken   as   the  standard 
figure  for  shellac,   determined  by  the  method  above 
described. 

As  it  is  an  accepted  principle  that  a  standard 
method  should  be  so  devised  that  its  inaccuracies 
shall  work  in  the  direction  of  favoring  the  seller  rather 
than  of  condemning  too  severely  the  article  sold,  it  is 
recommended  that  the  value  for  the  iodine  number  of 
rosin  be  taken  as  228.  The  result  of  using  in  this 
method  the  value  18  as  the  iodine  number  of  shellac 
and  228  as  the  number  of  rosin,  may  be  that  a  slightly 
lower  percentage  of  rosin,  under  some  circumstances, 
will  be  found  than  that  which  is  actually  present. 


174      PAINT  VEHICLES,   JAPANS  AND   VARNISHES 


The  percentage  of  rosin  is  determined  as  follows: 

Iodine  number  of  shellac  =  18 
Iodine  number  of  rosin  =  228 
Iodine  number  of  mixture  =  X 

(X  -  18) 


Percentage  of  rosin 


(228  -  18) 


277.   Insoluble  test  for  shellac.1     The  separation  of 
the  soluble  from  the  insoluble  portion  of  the  lac  is 

made  by  extracting  ap- 
proximately 5  g.  of  the 
lac  in  a  paper  cartridge, 
which  is  held  in  a  tube 
provided  with  a  siphon 
as  in  the  Knoefler  ex- 
traction apparatus,  and 
is  heated  by  the  vapors 
of  the  alcohol  which  pass 
around  the  tube  and 
are  then  condensed  by  a 
return  condenser  to  fall 
as  liquid  upon  the  shel- 
lac to  be  extracted.  The 
siphon  tube  should  be 
slightly  larger  than  the 
cartridge,  which  should 
be  supported  so  that  it 
does  not  rest  directly  on 
the  bottom. 

278.  Apparatus.  The 
most  convenient  appa- 
ratus for  carrying  out  the  process  is  illustrated  in  Fig.  8. 
It  consists  of  a  wide-neck  flask  in  which  is  suspended 
a  metal  return  condenser.  From  the  lower  part  of 
this  condenser  is  hung  a  siphon  tube  of  the  Knoefler 

1  A.S.T.M.  Standards,  1918,  p.  612. 


Depression 


FIG.  8.  —  APPARATUS  FOR  THE 
INSOLUBLE  TEST  FOR  SHELLAC 


ANALYSIS  OF  SHELLAC  AND  LACQUERS          175 

type.  A  Schleicher  and  Schuell  extraction  cartridge, 
No.  603,  26  mm.  in  diameter  by  60  mm.  high,  is  used 
in  a  siphon  tube  of  such  a  size  that  the  top  of  the 
cartridge  is  just  above  the  upper  curve  of  the  siphon, 
the  paper  thimble  being  cut  down  if  necessary.  It  is 
supported  on  three  indentations  in  the  glass  so  that 
there  is  a  little  space  underneath  and  around  the 
cartridge  to  allow  of  a  free  flow  of  liquid.  To  insure 
the  complete  extraction  of  all  matters  soluble  in 
alcohol  in  the  cartridge  itself,  it  should  be  thoroughly 
extracted  with  99.5  per  cent  methyl  alcohol  before 
use.  Then  place  the  cartridge  in  a  glass-stoppered 
weighing  bottle  and  dry  to  constant  weight  in  an  air 
bath  at  100°  C. 

279.  Procedure.  Place  a  sample  of  approximately 
5  g.  of  the  pulverized  lac  in  the  cartridge,  and  transfer 
to  the  extraction  apparatus.  Fill  the  cartridge  with 
cold  alcohol  of  the  character  described  to  a  point 
just  below  the  upper  curve  in  the  siphon.  The  cold 
alcohol  is  allowed  to  act  upon  the  lac  for  1  hour  before 
the  extraction  commences. 

Keep  the  alcohol  boiling  briskly  during  the  extrac- 
tion. The  rate  of  extraction  may  be  controlled  by 
the  use  of  an  electric  stove  of  the  Simplex  type,  4|  in. 
in  diameter,  and  using  the  full  current  of  2.2  amperes 
at  110  volts.  The  volume  of  methyl  alcohol  in  the 
flask  should  be  125  c.c.,  in  addition  to  the  alcohol 
required  to  fill  the  siphon.  Protect  the  flask  from 
drafts.  Under  these  conditions  the  tube  will  siphon 
over  about  33  times  in  1  hour.  The  condenser  should 
be  able  to  return  all  the  alcohol  volatilized  during  the 
vigorous  boiling  of  the  contents  of  the  flask,  the  object 
being  to  effect  the  maximum  extraction  during  the 
specified  time. 


176      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

280.  Time.    The  color  is  removed  by  the  end  of 
the  first  hour  in  practically  every  case  and  in  order 
to  eliminate  any  variations  due  to  difference  of  opinion 
as  to  the  exact  time  when  the  color  has  disappeared, 
the  total  extraction  period  shall  be  limited  to  exactly 
2  hours,  time  being  taken  from  the  moment  when  the 
first  siphon  tube  of  alcohol  has  passed  over.    After 
extraction,  place  the  cartridge  in  the  weighing  bottle, 
dry  to  constant  weight  at  100°  C.  and  weigh. 

281.  Calculation.    The   weight   of   the  residue  in- 
soluble in  alcohol  thus  obtained,  divided  by  the  weight 
of  the  sample,  and  this  quotient  multiplied  by  100,  is 
the  percentage  of  alcohol-insoluble  matter  in  the  lac. 

282.  Cautions   to   be   observed.     It  will  be  noted 
that  there  are  three  depressions  in  the  lower  part  of 
the  glass   extraction   thimble   to   hold   the   cartridge 
above  the  bottom.    This  is  very  necessary  for  the 
reason  that  during  the  early  part  of  the  extraction,  a 
very  free  flow  must  be  maintained  to  prevent  the 
blocking  of  the  siphon  with  the  wax,  which,  though 
readily  soluble  hi  hot  alcohol,  is  with  difficulty  soluble 
in  cold  alcohol.    The  object  in  filling  the  cartridge 
with  cold  alcohol,  before  starting  the  extraction  proper, 
is  to  allow  the  resin  and  some  of  the  wax  to  dissolve  at 
a  low  temperature.    If  the  higher  temperature  of  the 
boiling   alcohol   were   immediately   applied   it   would 
fuse  the  resin  into  a  lump  and  render  the  extraction 
difficult.    The    first    few    drops    of    distilled    alcohol 
which  fall  into  the  cartridge  will  cause  the  extract  to 
siphon  over,  thus  eliminating  the  bulk  of  the  resin  at 
the  start. 

283.  Determination  of  moisture  in  bleached  shel- 
lac.1   Both  orange  and  bleached  shellac  give  off  vola- 

1  A.  S.  T.  M.  Standards,  1918,  page  615. 


ANALYSIS   OF   SHELLAC   AND   LACQUERS          177 

tile  matter  at  temperatures  approaching  100°  C. 
Bleached  shellac  alters  chemically  at  these  tempera- 
tures, losing  its  solubility  in  alcohol.  For  these  rea- 
sons the  usual  methods  of  determining  moisture  by 
heating  in  the  ah-  bath  at  100  to  110°  C.  are  not  ap- 
plicable in  the  analysis  of  shellac. 

284.  Sampling.  Bleached  shellac  is  sold  in  three 
forms,  as  hanks  or  bars  containing  approximately  25 
per  cent  of  water,  as  ground  bleached  in  pulverized 
form  with  about  the  same  water  content,  and  as 
bone-dry  or  kiln-dried  shellac.  The  latter  is  prepared 
by  drying  the  ground-bleached  shellac  hi  the  air  or 
in  vacuum  driers  at  moderate  temperatures.  It  may 
contain,  depending  upon  the  completeness  of  the  dry- 
ing and  weather  conditions,  up  to  10  per  cent  or  more 
of  water. 

In  sampling  bone-dry  or  kiln-dried  bleached  shellac, 
a  fairly  large  portion  (about  1  Ib.)  should  be  taken 
from  different  parts  of  the  barrel  and  finely  ground 
by  running  quickly  through  a  coffee  mill.  No  attempt 
shall  be  made  to  sieve  it.  It  shall  be  rapidly  mixed 
and  transferred  to  a  Mason  jar  provided  with  a  screw 
cap  and  rubber  ring  seal.  The  jar  should  not  be 
more  than  two-thirds  full,  leaving  room  for  a  thorough 
mixing  by  shaking  the  contents.  It  shall  be  kept  in 
a  cool  place  and  tested  as  promptly  as  possible.  If  too 
warm  the  shellac  may  become  partly  caked,  in  which 
case  the  lumps  shall  be  broken  up  by  shaking  the  bottle. 

In  sampling  bars  or  hanks  it  is  recommended  that  a 
whole  hank  be  taken.  It  should  be  crushed  and 
ground  as  rapidly  as  possible.  Ground-bleached  shel- 
lac may  be  treated  as  above,  bearing  in  mind  that  the 
large  amount  of  moisture  present  makes  rapid  handling 
imperative. 


178      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

285.  Method  No.  1.     Weigh  from  5  to  10  g.  of  the 
sample  in  flat-bottom  dishes  about  4  in.  in  diameter 
or  in  watch  glasses  ground  to  fit  and  provided  with 
a  clamp.    "Spread  out  the  contents  of  the  dish  in  a 
thin  layer  to  expose  as  large  a  surface  as  possible. 
Place  the  shellac  in  a  desiccator  freshly  filled  with  con- 
centrated sulphuric  acid.    Exhaust  the  desiccator  by  a 
vacuum   pump   as    completely   as   possible.    With   a 
good  vacuum   (3   mm.   pressure   or  better)    constant 
weight  will  be  obtained  in  between  24  and  48  hours. 

Absolutely  dry  shellac  is  quite  hygroscopic  and  the 
final  weight  should  be  taken  as  rapidly  as  possible. 

286.  Method    No.    2.     The   same   results   may   be 
obtained  by  drying  the  shellac   in  a  well-ventilated 
air  bath  from  3  to  6  hours  at  100  to  110°F.  (38  to 
43°  C.).    One  or  two  electric  light  bulbs  provide  a 
convenient  source  of  heat.     The  temperature  should 
not  be  allowed  to  rise  above  43°  C.,  otherwise  sinter- 
ing may  occur  and  retard  drying.     With  poorly  ven- 
tilated   ovens    the    drying    may   take    much    longer. 
Completeness    of    drying    should    be    ascertained    by 
continuing  the  treatment  to  constant  weight. 

It  is  recommended  that  analysts  check  the  accuracy 
of  results  obtained  in  the  oven  by  comparison  with  a 
test  made  in  a  vacuum  desiccator  before  relying  exclu- 
sively on  the  oven. 

287.  Insoluble    test.     When   the   determination   of 
alcohol  insoluble  matter  in  bleached  shellac  is  required, 
the  sample  shall  be  dried  if  in  the  form  of  bars  or 
ground   bleached,    as   the   water   present   dilutes   the 
alcohol  to  a  point  where  solution  may  not  be  complete. 
Prolonged  heating  at  the  temperatures  of  38  to  43°  C. 
stated  above  may  render  the  shellac  partly  insoluble, 
and  it  is  recommended  that  in  preparing  shellac  for 


ANALYSIS  OF  SHELLAC  AND  LACQUERS    179 

this  determination  a  separate  portion  be  dried  by 
exposure  to  the  air  in  a  thin  layer,  without  the  appli- 
cation of  heat. 

288.  Substitute   shellacs.     Owing  to  the  compara- 
tive high  price  of  shellac,  innumerable  combinations 
of  other  gums  and  products  aside  from  rosin  have 
appeared  on  the  market.     Manila  cut  with  alcohol  is 
the  most  common  and  the  most  widely  used;  it  is  easily 
recognized  from  its  characteristic  odor.     It  should  be 
remembered  that  the  chief  use  of  shellac  varnishes  and 
shellac  substitutes  is  for  a  "first  coater," -which  is 
usually  "sanded"  and  therefore  the  most  important 
test  to  be  applied  to  such  substitutes  is  to  ascertain 
if  they  can  be  satisfactorily  "sanded"  without  gum- 
ming the  paper.    Very  few  substitutes  will  pass  this 
test,  which  is  the  reason  why  most  of  them  disappear 
from  the  market  in  a  short  time. 

289.  Lacquers.     The  manufacture  of  lacquers  is  an 
industry  in  itself  and  until  recently  has  been  developed 
apart  from  the  paint,  enamel  and  varnish  industries. 
Recent  industrial  developments  have  shown  that  there 
is  a  big  field  for  lacquers  and  numerous  paint  and 
varnish  concerns  have  taken  up  their  manufacture. 
Owing  to  the  wide  variety  of  solvents,  gums  and  other 
components  which  may  be  present  in  any  particular 
lacquer,  it  is  impossible  to  present  a  detailed  proce- 
dure that  would  be  satisfactory  under  all  circumstances. 
The  proximate  Analysis  of  Nitrocellulose  Solutions  and 
Solvents  by  Conley,  J.  Ind.  Eng.  Chem.  7,  p.  882,  and 
Analysis  of  Zapon  and  Celluloid  Lacquers  by  Zimmer, 
Kunstoffe  3,  p.  324,  present  definite  outlines  for  the 
examination  of  cellulose  products  which  the  author 
believes  will  be  found  satisfactory  hi  the  majority  of 
cases. 


CHAPTER  XIX 

ANALYSIS   OF  VARNISH  AND   ENAMEL  LIQUIDS 

290.  Difficulties   to   be    encountered.     The   author 
does  not  believe  that  a  purely  analytical  procedure 
can  be  developed  for  the  analysis  of  a  varnish  that 
will  prove  reliable,  which  has  for  its  purpose  the  dupli- 
cation of  the  varnish  or  its  correct  valuation. 

A  procedure,  however,  can  be  developed  which,  in 
the  hands  of  a  chemist  familiar  with  the  different 
gums  used  and  the  different  processes  and  details  of 
varnish  manufacture,  with  extensive  analytical  data 
obtained  from  varnishes  of  known  composition,  will 
prove  satisfactory  for  valuation  and  duplication. 
Several  such  schemes  are  now  in  use  by  varnish  chem- 
ists with  satisfactory  results.  The  scheme  outlined 
herewith  has  been  developed  and  used  by  the  author 
for  several  years  with  excellent  results  and  its  prac- 
tical value  is  becoming  increasingly  greater  with  the 
increasing  volume  of  comparative  data  that  is  being 
established.  For  obvious  reasons  the  author  cannot 
present  in  this  connection  the  comparative  data  he 
has  established,  or  certain  exact  details  of  manipula- 
tion as  they  are  based  on  the  varnish  formulas  and 
procedure  of  certain  corporations  or  are  derived  from 
other  confidential  sources  of  information. 

291.  Determination   of  volatile   thinner.     The  per- 
centage of  volatile  oils  present  and  their  characteris- 
tics are  best  determined  by  following  the  procedure 
given  in  Chapter  XIII. 

180 


ANALYSIS  OF  VARNISH  AND  ENAMEL  LIQUIDS     181 

292.  Determination  of  metallic  driers.     The  metal- 
lic driers  present  are  determined  as  in  Chapter  XVI 
beginning  with  section  226.     If  the  vehicle  has  been 
extracted   from   an   enamel   or   color  varnish   it  will 
usually  be  found  that  it  will  also  contain,  either  in 
combination  or  held  mechanically,  a  small  percentage 
of  the  pigments  used.     Zinc  and  lead  pigments  espe- 
cially enter   into    combination  with  the  vehicle  (see 
Chapter  XV).    Incineration  invariably  gives  an  ash 
which  will  be  materially  low  as  to  lead  content. 

293.  Separation  of  oil  and  resin.     If  it  is  desired  to 
determine  only  the  total  percentage  of  oil  and  of  gum, 
and  no  examination  is  to  be  made  of  the  nature  of 
each,  5  grams  only  of  the  varnish  need  be  taken  with 
a  corresponding  reduction  hi  the  amounts  of  alcoholic 
sodium  hydroxide  and  ether,  and  unless  it  is  a  very 
quick  drying  varnish,  or  grinding  Japan,  the  carbon 
dioxide  treatment  can  be  omitted. 

If  the  character  of  the  oil  and  gum  acids  is  to  be 
determined  the  following  procedure  is  followed.  Weigh 
by  difference  about  10  grams  of  the  varnish  into  a 
250-c.c.  Erlenmeyer  flask,  add  about  50  c.c.  water 
and  boil,  using  an  oil  bath  at  a  moderate  heat  until 
the  contents  of  the  flask  (uncovered)  have  been  re- 
duced to  a  total  of  about  15  c.c.  as  nearly  as  can  be 
judged.  A  moderate  stream  of  carbon  dioxide  gas 
should  be  passed  into  the  flask  to  prevent  oxidation 
during  the  evaporation,  50  c.c.  more  of  water  is  added, 
and  the  evaporation  again  repeated  in  an  atmosphere 
of  carbon  dioxide  to  a  volume  of  about  10  c.c.  This 
will  remove  practically  all  of  the  volatile  thinner. 
Occasionally  a  heavy  solvent  may  be  present  and  a 
small  percentage  of  the  high  boiling  point  petroleum 
fractions  will  remain.  The  allowance  to  be  made  and 


182       PAINT   VEHICLES,   JAPANS  AND   VARNISHES 

deducted  from  the  unsaponifiable  is  determined  from 
comparative  data  after  the  volatile  thinner  obtained 
as  described  in  section  173  has  been  distilled.  If  the 
product  is  a  grinding  Japan  or  an  especially  quick 
drying  varnish,  the  carbon  dioxide  treatment  must  be 
conducted  very  efficiently  to  prevent  oxidation. 

N 

294.  First   saponification.     Add   100   c.c.   of   —  al- 

2 

coholic  sodium  hydroxide  and  boil  under  a  reflux  con- 
denser for  3  hours.  With  some  varnishes  it  may  be 
necessary  to  use  15  to  25  c.c.  C.  P.  benzole  when  saponi- 
fying. Evaporate  to  a  bulk  of  about  20  c.c. 

Transfer  to  a  separatory  funnel,  using  a  policeman 
if  necessary,  washing  the  flask  thoroughly  with  water 
and  sulphuric  ether.  Dilute  to  about  200  c.c.  with 
warm  water  and  shake  until  the  soaps  have  dissolved. 
Cool  and  add  200  c.c.  sulphuric  ether  and  shake 
thoroughly,  but  carefully,  with  a  circular  motion  so  as 
not  to  form  an  emulsion  unduly  difficult  to  break  up. 
It  is  best  to  arrange  the  work  so  that  this  point  is 
reached  later  in  the  afternoon,  so  that  the  separation 
may  take  place  overnight.  If  an  emulsion  forms 
which  does  not  break  down  or  if  it  is  necessary  to 
hasten  the  separation,  alcohol  in  2  c.c.  portions  may 
be  added,  using  a  pipette  and  introducing  the  alcohol 
into  the  emulsion  portion. 

295.  First   unsaponifiable.     Draw  off   the  aqueous 
solution  into  a  larger  separatory  funnel  and  wash  the 
ether  solution  4  times  with  small  amounts  of  water, 
adding  the  washings  to  the  aqueous  solution  in  the  large 
funnel.     It  is  advisable  to  use  a  specially  arranged  ring 
stand  which  will  support  in  the  proper  positions  all 
the  separatory  funnels  that   are   used   in   the   entire 
separation,  •  as  considerable  time  is  saved  thereby. 


ANALYSIS  OF   VARNISH  AND  ENAMEL  LIQUIDS     183 

Draw  off  the  ether  solution  which  contains  part  of 
the  unsaponifiable  into  a  weighed  flask  and  set  aside 
until  later  in  the  analysis. 

296.  Recovery  of  mixed  oil  and  resin  acids.     Acidify 
the  aqueous  solution  with  hydrochloric  acid  and  ex- 
tract 4  tunes  with  ether,  using  about  40-c.c.  portions. 
Wash  the  combined  ether  portions  4  times  with  water. 
Discard  the  aqueous  solution  and  aqueous  washings. 

Transfer  the  ether  solution  to  a  150-c.c.  Erlenmeyer 
flask  and  distill  off  the  ether,  using  an  oil  bath  heated 
by  an  electric  hot  plate.  When  the  bulk  of  the  ether 
has  been  removed,  uncork  the  flask  and  continue  the 
evaporation  with  the  flask  open  and  with  an  atmo- 
sphere of  carbon  dioxide.  Finally  use  two  10-c.c.  por- 
tions of  absolute  ethyl  alcohol  to  remove  the  last  traces 
of  moisture.  Not  only  is  it  necessary  to  prevent  oxi- 
dation but  the  temperature  must  not  exceed  105°  C. 
in  order  to  prevent  polymerization  of  tung  oil  acids, 
which  may  be  present.  If  the  moisture  is  not  com- 
pletely removed,  the  esterification  which  is  the  next 
step  will  not  be  sufficiently  complete. 

297.  Esterification.     The  esterification  can  be  con- 
ducted according  to  the  well  known  Twitchell  method 
with  very  careful   attention   to   detail,  using  hydro- 
chloric acid  gas  that  has  been  carefully  dried.    The 
author  has  found  Wolff's   method1   equally  efficient 
and  much  more  rapid  and  satisfactory.    Dissolve  the 
residue  in  40  c.c.  absolute  alcohol  and  add  40  c.c.  of  a 
mixture  of  1  part  cone,  sulphuric  acid  to  4  parts  abso- 
lute alcohol.     Heat  quickly  to  boiling  and  boil  for  4 
minutes  under  a  reflux  condenser.     If  absolute  ethyl 
alcohol  is  used  great  .care  must  be  taken  to  preserve 
it  and  the  acid-alcohol  mixture  from  absorbing  mois- 

1  Chem.  Ztg.,  38,  pages  3G9-370,  382-383. 


184      PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

ture.  To  avoid  these  difficulties  the  author  has  used 
absolute  methyl  alcohol,  using  only  the  best  procur- 
able grade. 

Completely  transfer  the  contents  of  the  flask  at  once 
to  a  separatory  funnel,  washing  the  flask  with  ether 
and  water,  add  150  c.c.  ether,  and  after  agitation  add 
100  c.c.  of  a  ten  per  cent  solution  of  sodium  chloride. 
Draw  off  the  aqueous  portion,  repeat  the  extraction 
with  two  successive  50-c.c.  portions  of  ether.  Discard 
the  aqueous  solution  and  wash  the  combined  ether 
portions  twice  with  water  and  discard  the  aqueous 
washings. 

298.  Separation    of    fatty    acid    esters    from    resin 

N 

acids.     To  the  ether  solution  add  100  c.c.  of  —  aqueous 

o 

sodium  hydroxide.  Shake  thoroughly  and  allow  to 
separate,  then  repeat  the  shaking.  After  separating 
draw  off  the  aqueous  solution  into  another  separatory 
funnel.  Wash  the  ether  solution  twice  with  75  c.c. 

N 

water  containing  5  c.c.  alcohol  and  5  c.c.  of  the  — 

o 

sodium  hydroxide.  Add  these  washings  to  the  main 
aqueous  solution. 

The  ether  solution  contains  the  methyl  or  ethyl 
esters  of  the  fatty  acids,  depending  on  the  alcohol 
used,  and  part  of  the  unsaponifiable.  The  aqueous  so- 
lution contains  the  resin  acid  soaps.  If  insoluble 
soaps  are  formed  when  the  ether  solution  is  treated 

N 

with  the  —  sodium  hydroxide  they  are  to  be  carried 
o 

along  into  the  final  resin  soap  solution. 

299.  Resin  soaps.     Extract  the  aqueous  resin  soap 
solution  with  two  75-c.c.  portions  of  ether  and  add 


ANALYSIS  OF  VARNISH  AND  ENAMEL  LIQUIDS     185 

to  the  main  ether  solution  and  wash  the  combined 
ether  portions  with  water.  The  combined  aqueous 
solution  and  washings  are  preserved  in  a  separately 
funnel  for  the  subsequent  liberation  of  the  resin  acids. 

300.  Second  saponification.     The  ether  solution  con- 
taining the  esters  is  transferred  to  a  small  Erlenmeyer 
flask  and  the  ether  distilled  off,  using  the  same  pro- 
cedure as  in  section  296  except  that  the  final  traces  of 
moisture  need  not  be  removed  with  alcohol.    To  the 

N 

residue  are  added  immediately  50  c.c.  —  alcoholic  so- 
dium hydroxide  and  boiled  under  a  reflux  condenser 
for  45  minutes. 

Evaporate  rapidly  from  open  flask  on  electric  hot 
plate  to  a  bulk  of  approximately  15  c.c.,  dilute  -with 
100  c.c.  warm  water,  and  transfer  to  separatory  funnel, 
rinsing  flask  with  water  and  ether.  Cool,  extract 
four  times  with  ether  and  wash  the  combined  ether 
extract  thoroughly  with  small  portions  of  water. 
These  aqueous  washings  are  added  to  the  main  aque- 
ous solution.  This  solution  contains  the  soaps  of  the 
fatty  acids. 

301.  Second   unsaponifiable.     The  combined  ether 
extract  from  preceding  section  contains  the  balance  of 
the  unsaponifiable  and  is  added  to  the  ether  solution 
containing   the  first  unsaponifiable   (see  section  295). 
The  ether  is  distilled  off,  two  5-c.c.  portions  of  abso- 
lute alcohol  are  added  to  remove  all  traces  of  moisture, 
heated  carefully  until  all  the  alcohol  has  disappeared, 
cooled  and  weighed  as  total  unsaponifiable.     When  the 
bulk  of  the  ether  has  been  distilled  off,  it  is  preferable 
to  transfer  to  a  50-c.c.  Erlenmeyer  flask  and  the  deter- 
mination finished  in  this  flask,  as  the  flask  has  to  be 
crushed  for  the  identification  treatment  of  the  gums. 


186      PAINT   VEHICLES,   JAPANS  AND  VARNISHES 

302.  Recovery  of  the  oil  acids.     The  aqueous  solu- 
tion containing  the  soaps  of  the  fatty  acids  is  acidified 
with  hydrochloric  acid  and  extracted  thoroughly  with 
ether  in  the  usual  manner.     Discard  the  aqueous  por- 
tions.   Transfer  to  a  small  Erlenmeyer  flask,  distil  off 
the  bulk  of  the  ether,  disconnect  flask,  introduce  cur- 
rent of  carbon  dioxide,   evaporate  the  remainder  of 
the  ether,  add  two  5-c.c.  portions  of  absolute  alcohol 
to  remove  traces  of  moisture,  heat  at  105°  C.  to  con- 
stant weight  in  current  of  carbon  dioxide.    This  tem- 
perature should  not  be  exceeded  or  maintained  longer 
than  necessary  because  of  its  effect  on  the  tung  oil 
acids  that  may  be  present.    The  residue  is  weighed 
as  the  fatty  acids  and  preserved  in  an  atmosphere  of 
carbon  dioxide  if  an  estimation  of  the  tung  oil  acids 
is  to  be  made.    This  weight  of  the  fatty  acids  plus 
the  weight  of  any  oxidized  fatty  acids  obtained  in 
section  304  can  be  taken  as  equivalent  to  the  weight 
of  oil  present  in  the  varnish  as  a  small  percentage  of 
the  gum  constituents  remain  with  the  oil  acids  and 
substantially  compensate  for  the  glycerine  content  of 
the  oil. 

303.  Recovery   of   the    resin    acids.     The   aqueous 
solution  of  the  resin  acid  soaps  set  aside  from  section 
299  is  acidified  with  hydrochloric  acid  and  extracted 
with  three  50-c.c.  portions  of  ether,  the  combined  ether 
portions  washed  twice  with  water  and  distilled,  trans- 
ferring completely  to  a  weighed  50-c.c.  Erlenmeyer  flask 
after  the  larger  part  of  the  ether  has  been  distilled. 
The  last  traces  of  moisture  are  removed  with  abso- 
lute alcohol  and  the  evaporation  carried  out  hi  an 
atmosphere  of  carbon  dioxide  at  120°  C.  to  constant 
weight.     This    residue    constitutes    the    resin    acids 
which,  plus  the  unsaponifiable  (any  petroleum  residue 


ANALYSIS  OF   VARNISH  AND  ENAMEL   LIQUIDS     187 

present  having  been  deducted)  multiplied  by  the 
proper  factor  determined  by  the  nature  of  the  gum 
acids,  gives  the  amount  of  gum  present  in  the  varnish. 
Boughton l  uses  the  empirical  factor  of  1.07.  The 
flask  containing  the  gum  acids  is  preserved  for  subse- 
quent examination  as  to  their  nature. 

304.  Oxidized  fatty  acids.     Oxidized  fatty  acids  do 
not  esterify  readily  and  if  there  is  reason  to  believe 
that  the  varnish  contains  an  oxidized  oil  hi  quantity 
or  in  case  of  doubt,  the  resin  acids  obtained  in  the 
preceding  section  should  be  given  a  second  esterifica- 
tion  following  the  procedure  as  previously  stated  be- 
ginning  with   section   297    and   observing   the   same 
cautions.     The  weight  of  oxidized  oils  thus  obtained 
should  be  added  to  the  weight  of  acids  recorded  in 
section  302  and  the  resin  acids  after  separation  pre- 
served for  further  examination. 

305.  Sulphurized  oils.     The  use  of  sulphurized  oils 
in  paint  and  enamel  vehicles  is  becoming  increasingly 
common.     Their   presence   can  be   detected   and  the 
approximate  percentage  present  can  be  ascertained  by 
determining  the  percentage  of   combined  sulphur  in 
the  vehicle.     Thoroughly  sulphurized  oils  usually  con- 
tain 6  to  7  per  cent  of  combined  sulphur,  this  amount 
being   sufficient    to   produce  a    satisfactory   "body," 
so  that  one  part  of  oil  will  take  one  to  two  parts  of 
volatile  thinner  and  still  have  a  medium  consistency. 

306.  Procedure.     Intimately  mix  by  grinding  in  a 
mortar  0.5  gram  of  the  nonvolatile  portion  of  the  oil, 
or  1  gram  of  the  original  oil  with  3  grams  of  Eschka's 
mixture  (2  parts  light  calcined  magnesium  oxide,  sul- 
phur-free, and  1  part  dry  sodium  carbonate).     Trans- 
fer completely  to  a  porcelain  crucible,  cover  with  a 

1  Bureau  of  Standards,  Technologic  Paper  No.  65,  page  26. 


188      PAINT  VEHICLES,  JAPANS  AND  VARNISHES 

layer  of  0.5  gram  of  the  Eschka  mixture,  and  heat 
gently  with  an  alcohol  lamp  near  the  top  of  the  mix- 
ture. No  smoke  must  appear  and  no  darkening  of 
the  cover  layer  must  occur.  A  gas  flame  cannot  be 
used  because  it  contains  sufficient  sulphur  to  affect 
the  determination.  Gradually  rotate  the  crucible,  so 
that  all  portions  of  the  mass  receive  a  uniform  heat- 
ing. After  heating  until  dark  particles  do  not  appear 
on  stirring,  the  contents  are  removed  to  a  mortar  and 
again  finely  ground,  then  transferred  to  a  platinum 
crucible  and  again  heated,  but  not  above  a  very  faint 
red  for  several  hours.  Cool,  empty  into  a  300-c.c. 
beaker,  digest  on  a  water  bath  with  100  c.c.  water 
for  30  minutes.  Filter  and  wash  the  residue  with 
four  20-c.c.  portions  of  boiling  water.  Wash  thor- 
oughly on  the  filter. 

Add  5  c.c.  bromine  water  to  filtrate,  make  just 
distinctly  acid  with  hydrochloric  acid,  heat  until  the 
bromine  is  entirely  expelled,  precipitate  with  barium 
chloride  solution  hi  the  usual  manner.  Filter,  wash, 
ignite,  and  wreigh  as  barium  sulphate  and  calculate 
to  S.  A  blank  should  be  run  on  the  Eschka  mixture 
itself  and  such  correction  applied  as  may  be  necessary. 
If  the  room  is  free  from  sulphur  compounds  and  the 
heating  during  the  burning  off  is  carefully  regulated 
and  is  sufficiently  low  during  the  first  part  of  the 
operation,  accurate  results  can  be  obtained. 


CHAPTER  XX 

ANALYSIS   OF  VARNISH   AND   ENAMEL  LIQUIDS 
(Continued) 

307.  Separation  of  the  oil  acids.     A  small  portion 
should  be  taken  and  the  iodine  number  determined 
as  in  the  chapter  devoted  to  tung  oil.    The  balance  is 
treated    by    the     Ware-Schumann    potassium    soap 
method1  as  follows: 

The  oil  acids,  not  exceeding  3  grams,  are  saponified 

N 
with  100  c.c.  —  absolute  alcoholic  potash  for  1  hour, 

the  end  of  the  return  condenser  being  connected  to  a 
calcium  chloride  tube  to  prevent  moisture  absorption. 
The  saponified  mixture  is  cooled  to  0°  C.,  held  for  10 
minutes  at  that  temperature,  and  filtered  through  a 
Gooch  crucible,  using  a  filter-paper  disk  instead  of 
an  asbestos  pad.  The  precipitate,  after  washing 
thoroughly  with  ice-cold  saturated  absolute  alcohol, 
is  removed  from  the  crucible  to  a  cover  glass,  and  is 
dried  at  75  to  80°  C.,  under  vacuum.  After  cooling 
without  removing  from  the  desiccator,  the  precipitate 
is  taken  out  and  weighed,  and  the  weight  calculated  to 
tung  oil. 

308.  Cautions  to  be  observed.     It   is  necessary  to 
use  absolute  alcohol  both  for  saponification  and  for 
washing  the  precipitate,   as  the  soap  is  appreciably 
soluble   in   the   presence   of   even   small   amounts   of 
water.     This  alcohol  and  alcoholic  potash  should  be 

1  J.  Ind.  and  Eng.  Chem.,  Vol.  6,  p.  806. 


190      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

freshly  saturated  with  the  soap  before  use,  for  although 
the  soap  is  but  slightly  soluble  in  absolute  alcohol, 
that  solubility  changes  on  standing,  especially  if  ex- 
posed to  light.  It  is  a  comparatively  easy  matter  to 
keep  freshly  saturated  solutions  ready  for  use  by 
making  up  a  batch  of  the  soap  and  introducing  it 
into  the  stock  bottles  of  alcohol  and  alcoholic  potash, 
in  quantities  more  than  sufficient  to 
saturate  them  at  0°  C.  When  about  to 
make  a  determination,  the  solution  may 
be  warmed  until  an  appreciable  amount 
of  soap  goes  into  solution,  after  which 
it  may  be  cooled  to  0°  C.  and  held  for 
10  minutes  and  filtered.  This  fresh 
nitrate  is  ready  for  use. 

During  the  washing  of  the  precipitate 
the  whole  mass  must  be  kept  cold,  for 
the  solubility  of  the  material  in  alcohol 
is  greatly  increased  by  a  rise  in  tem- 
perature. This  is  accomplished  by 
filtering  through  a  Gooch  crucible  sur- 
rounded by  cracked  ice  (see  Fig.  9) . 

The    precipitate    is    susceptible    to 
oxidation  and  must  be  kept  away  from 
air  during  drying.     Also,  the  fact  that  high  temperature 
will  char  the  soap  limits  the  drying  temperature  to 
about  80°  C. 

The  weight 'of  potassium  soap  obtained  is  calculated 
to  tung  oil  by  comparing  with  the  amount  obtained 
from  putting  3  grams  of  standard  tung  oil  through  the 
above  treatment  with  alcoholic  potash  and  with  the 
same  careful  attention  to  detail. 

309.  Separation  of  gum  constituents.  The  flask 
containing  the  weighed  resin  acids  is  crushed  carefully 


ANALYSIS   OF  VARNISH  AND  ENAMEL  LIQUIDS     191 

and  very  finely  ground  in  a  mortar  with  clean  white 
sand.  This  mixture  is  placed  in  a  cartridge  and  ex- 
tracted for  24  hours  with  redistilled  pentane  (Standard 
Oil  Co.),  the  higher  boiling  point  portion  of  which  has 
been  discarded.  The  pentane  is  evaporated  and  the 
residue  weighed. 

The  acid  number  of  the  residue  is  determined  by 
dissolving  in  C.  P.  benzol  and  alcohol  and  titrating 
with  alcoholic  potash.  A  blank  titfation  should  also 
be  run  on  the  alcohol. 

The  neutral  solution  is  acidified  with  hydrochloric 
acid,  extracted  with  ether,  and  the  resin  acids  sub- 
mitted to  further  solubility  tests  with  various  aqueous 
alkaline  solutions  and  other  solvents,  depending  on 
the  data  already  established.  The  flask  containing 
the  total  unsaponifiable  is  crushed,  ground  with  sand 
and  given  a  similar  extraction  with  the  pentane. 

310.  Identification  of  constituents.  Having  estab- 
lished the  percentage  of  unsaponifiable  and  of  resin 
acids,  the  solubilities  of  each,  the  acid  value  of  the 
original  nonvolatile  and  of  the  resin  acids,  and  com- 
paring these  results  with  data  from  numerous  var- 
nishes of  known  composition,  the  nature  of  the  gums 
used  and  the  treatment  the  oil  portion  has  received 
can  be  determined  with  a  fair  degree  of  accuracy. 
This  is  based  on  the  assumption  that  the  analyst  has 
an  intimate  knowledge  of  the  different  procedures 
used  with  the  various  gums  and  oils  in  varnish  manu- 
facture and  has  adequate  data  on  the  losses  and 
changes  that  take  place  during  their  heat  treatments. 

Recently  varnishes  containing  synthetic  resins  have 
appeared  on  the  market.  From  the  desirable  qualities 
which  these  varnishes  possess  it  is  a  fair  assumption 
that  they  will  have  a  wide  usage  in  the  near  future. 


192      PAINT  VEHICLES,   JAPANS  AND   VARNISHES 

These  resins,  which  are  of  the  cumarone  type,  are  al- 
most wholly  unsaponifiable  and  therefore  will  be  found 
in  the  first  unsaponifiable  (see  section  295)  and  the 
varnish  containing  such  resins  will  have  a  proportion- 
ally low  acid  value. 

It  should  be  remembered  that  the  above  described 
analytical  procedure  requires  considerable  quantities 
of  ether  almost  continuously  throughout  the  analysis 
and  all  due  precautions  should  be  adopted  against  fire 
and  explosions. 

311.  Kauri  test  for  estimating  percentage  of  oil. 
The  percentage  of  oil  in  a  varnish  or  enamel  liquid 
can  be  determined  with  a  fair  degree  of  approxima- 
tion without  analysis  by  means  of  the  Pulsifer  Kauri 
Solution  Test  used  in  spec.  14,001-B,  Spar  Varnish 
Signal  Corps,  U.  S.  A.  A  series  of  varnishes  of  known 
composition  are  selected  and  the  minimum  amount  of 
a  suitable  prepared  oil  is  determined  which  is  neces- 
sary to  add  to  each,  to  enable  it  to  just  pass  the  speci- 
fied bending  test,  after  adding  50  per  cent  by  weight 
of  the  kauri  solution,  the  nonvolatile  portion  of  the 
varnish  plus  the  added  oil  being  considered  as  100 
per  cent.  If  the  varnish  or  enamel  liquid  is  very 
long  in  oil,  no  added  oil  will  be  necessary  and  the 
amount  of  kauri  solution  added  is  increased  to  the 
point  where  the  mixture  will  just  pass  the  bending 
test. 

The  varnish  under  examination  is  compared  for 
body,  drying,  etc.,  with  the  above  selected  varnishes, 
the  percentage  of  volatile  is  determined  and  a  series 
of  3  or  4  tests  made  up  by  adding  weighed  amounts 
of  prepared  oil  to  the  varnish  as  judged  by  the  above 
comparison.  One-half  as  much  by  weight  of  the 
kauri  solution  is  added  as  the  total  of  nonvolatile  in 


ANALYSIS  OF  VARNISH  AND  ENAMEL  LIQUIDS     193 

the  varnish  plus  weight  of  added  oil  and  the  tests 
are  completed  as  described  herewith.  The  test  which 
just  passes  the  bending  operation  is  the  one  to  be 
used  in  calculating  the  percentage  of  oil  present  as 
compared  with  the  varnishes  of  known  composition. 

312.  Preparation    of    the    Pulsifer    kauri    solution. 
The  kauri  solution  is  made  as  follows:    Arrange  a  dis- 
tillation   flask    condenser    (water    cooled)    and    tared 
receiver  for  distillate  on  balance.     Place  in  flask  about 
|  of  its  volumetric  capacity  of  clean  bright  pieces  of 
No.  1  kauri  broken  to  pea  size.    Melt  and  distill  care- 
fully until  25%  by  weight  is  driven  off.    At  the  end 
of  the  distillation  the  thermometer  in  the  distillation 
flask  with  bulb  at  the  level  of  the  discharging  point 
of  the  flask  should  register  approximately  700  degrees  F. 

Pour  the  residue  into  a  clean  pan  —  when  cold 
break  up  and  dissolve  one  part  of  the  run  kauri  in 
two  parts  of  pure  spirits  of  turpentine  by  weight  (at 
a  temperature  of  approximately  300  degrees  F.). 
This  solution  should  be  made  in  a  carefully  tared 
beaker  and  brought  back  to  correct  weight  when  cold 
by  the  addition  of  the  amount  of  spirits  of  turpentine 
necessary  to  replace  the  loss  by  evaporation  during 
the  dissolving  of  the  gum.  If  properly  prepared  all  of 
the  gum  will  remain  in  solution. 

313.  Procedure.      Determine  the   nonvolatile   con- 
tent  of   the   varnish  under   examination.    Take   100 
grams  of  the  varnish  and  add  to  it  an  amount  of  the 
kauri  solution  equivalent  to    50   per  cent  by  weight 
of  the  nonvolatile    plus  weight    of   added  oil.    Mix 
carefully   and   thoroughly   without   warming.     If   for 
example  100  g.  of  the  varnish  contain  45  g.  nonvola- 
tile matter  and  5  g.  of  oil  are  added,  50  grams  of  the 
kauri  solution  will  be  required. 


194      PAINT  VEHICLES,   JAPANS  AND  VARNISHES 

Flow  a  coat  of  the  varnish  thus  reduced  on  a  tin 
panel  of  suitable  size  and  weight  (4x5  inches,  100- 
Ib.  tin).  Allow  to  dry  in  a  nearly  vertical  position  at 
room  temperature  for  one  hour.  Then  place  hi  an 
oven  (at  200  to  212  degrees  F.)  in  a  horizontal  position 
and  bake  for  5  hours  at  this  temperature.  Remove 
and  allow  to  cool  at  room  temperature  (not  less  how- 
ever than  70  degrees  F.)  for  one  hour. 

Place  the  panel  at  a  point  approximately  midway 
between  the  top  and  bottom  edges  (of  the  panel)  over 
a  |"  rod  (held  firmly  between  suitable  supports)  and 
bend  double  rapidly.  This  bending  should  be  done 
at  a  temperature  not  lower  than  70  degrees  F.  and  if 
possible  not  over  80  degrees  F.  The  varnish,  to  pass 
the  test,  must  show  no  cracking  whatever  at  the 
point  of  bending.  Cracking  may  best  be  detected  by 
observing  the  bent  panel  held  closely  at  the  proper 
angle  under  a  shaded  artificial  light  using  a  magnify- 
ing glass. 

With  experience  and  adequate  facilities  the  entire 
test  can  be  run  in  one  day  and  the  results  will  be  suffi- 
ciently accurate  for  most  purposes. 

314.  References.  The  following  references  are  of 
interest  as  they  deal  with  various  phases  of  varnish 
and  enamel  liquid  analysis. 

BOCHARD  and  GILLETT.     Essai  et  Critique  de  la  M6thode  Mcllhiney 
pour  1'Analyse  de  Vernis  Gras. 

Proc.  8th  Internat.  Cong.  Appl.  Chem.  12,  p.  7  (1912). 
BOUGHTON.     Detection  of  Resin  in  Drier. 

Technologic  Paper  No.  66,  Bureau  of  Standards. 
BOUGHTON.     Determination  of  Oil  and  Resin  in  Varnish. 

Technologic  Paper  No.  65,  Bureau  of  Standards. 
DARNER.     Method  of  Varnish  Analysis. 

N.  Dak.  Ag.  Exp.  St.  Paint  Bulletin  No.  1,  p.  108  (1915). 
DE  WAELE  and  SMITH.     Determination  of  Volatile  Thinners  in  Oil 
Varnishes. 

Analyst  42,  p.  170  (1917). 


ANALYSIS   OF   VARNISH  AND  ENAMEL   LIQUIDS     195 

DIETRICH.     Analysis  of  Resins,  Balsams,  and  Gum  Resins  (1901). 
GILL.     Determination  of  Resin  in  Varnishes. 

J.  Am.  Chem.  Soc.  28,  p.  1723  (1906). 
HOLLEY.     Adulteration  of  Chinese  Wood  Oil. 

Drugs,  Oils  and  Paints,  XXXI,  p.  327  (1916). 
HOLLEY  and  ROBERTS.     Composition  of  Chinese  Wood  Oil. 

Drugs,  Oils  and  Paints,  XXXI,  June,  1916. 
INGLE.     Oxidation  of  Oils. 

J.  Soc.  Chem.  Ind.,  p.  639,  1913. 

LEWKOWITSCH.     Determination  of  the  Glycerol  Yield  with  Subsequent 
Calculation  of  the  Oil  Content. 

Chem.  Tech.  and  Anal.,  Oils,  Fats  and  Waxes,  III,  p.  164  (1915). 
LIVACHE  and   MC!NTOSH.      Manufacture  of  Varnishes  and  Kindred 

Industries. 
MclLHiNEY.     Analysis  of  Oil  Varnishes. 

Proc.  Am.  Soc.  for  Test.  Mat.  8,  p.  596  (1908). 
MORRELL.     Polymerized  Drying  Oils. 

J.  Soc.  Chem.  Ind.,  p.  105,  1915. 

PEARCE.     A  Study  of  the  Fatty  Acids  Obtained  from  Varnish  Oils  and 
from  Varnishes. 

J.  Ind.  Eng.  Chem.  11,  p.  121  (1919). 
PEARCE.     Method  of  Varnish  Analysis. 

J.  Ind.  Eng.  Chem.  11,  p.  200  (1919). 
SCHUMANN.     Polymerization  of  Chinese  Wood  Oil. 

J.  Ind.  Eng.  Chem.  8,  p.  5  (1916). 

SEATON,    SAWYER    and    PROBECK.    Varnish    Analysis    and    Varnish 
Control. 

J.  Ind.  Eng.  Chem.  8,  p.  490,  9,  p.  35. 
WARE.     Optical  Dispersion  of  Chinese  Wood  Oil  as  an  Index  of  Purity. 

J.  Ind.  Eng.  Chem.  8,  p.  126  (1916). 

WARE  and  CHRISTMAN.     Errors  hi  Determination  of  Acid  Values  of 
Varnishes  and  Boiled  Oils. 

J.  Ind.  Eng.  Chem.  8,  p.  996. 
WARE  and  SCHUMANN.     Constitution  of  Chinese  Wood  Oil  Varnishes. 

J.  Ind.  Eng.  Chem.  7,  p.  571. 
WARE  and  SCHUMANN.     Examination  of  Chinese  Wood  Oil. 

J.  Ind.  Eng.  Chem.  6,  p.  806  (1914). 
WOLFF.     A  Contribution  to  the  Analysis  of  Oil  Varnishes. 

Farben  Ztg.  21,  1302  (1916). 

WOLFF  and  SCHOLZE.     Estimation  of  Colophony  in  Varnishes,  Oils 
and  Soaps. 

Chem.  Ztg.  38,  pp.  369-370,  382-383  (1914). 


ADDENDA 

VOLUME  EQUIVALENTS 

1  liter  =  1000  cu.  cm. 
=  .  03531  cu.  ft. 
=  61.022  cu.  in. 
=  .2642  gal. 

=  2.2021bs.  water  15°  C. 
1  cubic  centimeter  =  .  001  liter 

=  .  06102  cu.  in. 
=  .00026  gal. 
=  .  00022  Ib.  water  15°  C. 
1  cubic  inch  =  .  0164  liter 

=  16.388cu.  cm. 
=  .00433  gal. 
=  .  03608  Ib.  water  15°  C. 
1  gallon  =3. 785  liters 
=  3.785  cu.  cm. 
=  231  cu.  in. 

=  8.3381bs.  water  15°  C. 
1  liquid  oz.  =29.57  cu.  cm. 
1  liquid  qt.  =0.9463  liter 
1  liter    =  1.0567  liq.  qt. 

GRAVIMETRIC  EQUIVALENTS 

1  gram  =  .  03527  oz. 

=  .  0022046  Ib. 
1  ounce  =28.35  grams 

=  .06251b. 
1  pound  =  453.6  grams 


196 


INDEX 

A  PAGE 

Abel  Pensky  Tester 26 

Acetate  of  lead 113, 138 

Acetone,  Messinger's  method  for 45 

uses  of 44 

Acetone  oils 46 

distillation  of 47 

Agricultural  paste  paints 103 

Air-drying  Japans 154 

Aldehyde-free  alcohol 123 

Aluminum,  oleate Ill 

stearate Ill 

Asphaltums 158 

characteristics  of 158 

fixed  carbon  of 161 

B 

Baking  Japans 154 

analysis  of  volatile  portion  of 157 

coal  tar  distillates  in 163 

estimation  of  gums  in 158 

estimation  of  metallic  driers  in 165 

estimation  of  oil  in 163 

oils  used  in 164 

volatile  content 155 

Benzol,  distillation  of 49 

evaporation  of 51 

specific  gravity  of 49 

uses  of 49 

Bleached  shellac,  moisture  in 176, 178 

insoluble  test  for 178 

sampling  of 177 

Blown  oils 77 

Boiled  oils 76 

Bone  pitches 158 

Borate  of  manganese 138, 142 

Borax 114 

Browne's  method 87 

197 


198  INDEX 

C  PAGE 

Calcium 153 

Carbonate  of  soda 113 

Casein 110 

Caustic  soda 113 

Centrifuge,  use  of 98 

Chinese  Wood  oil 79 

Chloride  of  lime 112 

Cobalt 152 

acetate 138 

resinate 143 

Copper 146 

Corn  oil 128 

Cottonseed  oil 128 

Cumarone  resins 191 

D 

Denatured  alcohol 35 

composition 35 

correction  for  temperature 38 

specific  gravity  of 36 

Determination  of  true  red  lead  content 139 

Distemper  colors 104 

Driers 130 

E 

Effect  of  emulsifying  agents 133 

Effect  of  storage  on  drying  oils 136 

Emulsifiers. 109 

classification  of 110 

effect  of 131, 133 

need  for 131 

Emulsion  paints,  deterioration 110 

F 

Fish  oil 92 

determination  of 93 

Foots ; 61 

estimation  of 62,  63 

in  South  American  seed 63 

Free  asphaltous  acids 163 

Free  fatty  acids 123 

iodine  number  of 137 

Free  mineral  acids  in  oils 123 

Ferrous  sulphate  solution,  preparation  of 150 


INDEX  199 

G  PAQB 

Glue 110 

Glycerine 112 

Graining  compounds 104 

Grinding  oils 77 

Gravimetric  equivalents 196 

H 

Halphen  test 169 

Hanus'  method 58 

Heckel's  modification  of  Ford-Williams'  method 142 

Hiibls'  method 60 

Hydrolysis,  effect  of 76 

if  lead  soaps 132 

of  zinc  soaps 132 

I 

Iodine  monochloride 171 

Iodine  number 122 

Iron  linoleate 151 

L 

Lacquers 179 

Lead 145 

compounds  of 139 

oleate Ill 

stearate Ill 

Libermann-Storch  reaction 129, 168 

Linseed  oil,  acid  number  of 56 

bodied 77 

constants  of 53,  63 

density  of 55 

fatty  acids,  preparation  of 65 

flash  point  of 124 

foots 64 

from  South  American  seed 54 

hexabromide  number  of 65 

iodine  number  of 58 

methods  of  testing 54 

refractive  index  of 58 

saponification  number  of 56 

specifications  for 53 

specific  gravity  of 54 

unsaponifiable  in 57 


200  INDEX 

PAGE 

Linseed  oil,  uses  of 52 

Litharge 138 

Lumbang  oil ' 93 


Manganese 146 

Menhaden  oil 92, 128 

analytical  constants  of 93 

Messinger's  method 45 

Methyl  acetate,  estimation  of 46 

Methyl  alcohol,  estimation  of  in  mixtures 42 

Mineral  oil 125 

estimation  of 126 

Outerbridge  test  for 127 

separation  from  rosin  oil 126 

Mineral  spirits,  War  Department  specifications  for '.  26 

N 

Nitrocellulose  solutions 179 

O 

Obtaining  uniform  sample 96 

Oils,  oxidation  of 102 

Oxide  of  manganese 138 

estimation  of 141 

Oxidized  fatty  acids 187 

Oxygen  absorption  of  oils 129 

P 

Paint,  puttied 134 

Perilla  oil 94 

Permanganate  solution 149 

Petroleum  pitches 158 

blown 159 

Petroleum  thinners,  distillation  of 14, 15, 20 

temperature  corrections  for 5 

color  of 2 

odor  of 1 

solvent  strength  of 2 

specific  gravity  of 3 

Phosphate  of  soda 114 

Pine  oil 31 

analysis  of 33 


INDEX  201 


Pine  oil,  distillation  of 33 

in  petroleum  products 33 

water  in 32 

Pulsifer  test 192 

R 

Reactions  in  paint  on  storage 133 

Red  lead 138 

Reducing  oils 94, 130 

References 194 

Rosin 129 

Rosin  oil 129 

Outerbridge  test  for 127 

Rosinates 134 

colloidal  formation  of 135 

S 

Separation  of  oil  for  determination  of  its  constants 101 

Separation  of  pigment 97 

Separation  of  vehicle  from  pigment 96 

Shellac,  adulteration  of 173 

insoluble  test  for 174 

iodine  absorption  of 173 

substitutes 179 

valuation  of 167 

varnishes  body  of 167 

detection  of  rosin  in 168 

estimation  of  rosin  in 170 

Solvent  naphtha 50 

Soya  bean  oil -. 91, 129 

analytical  constants  of 92 

uses  of 91 

Specification  paints 121 

Specific  gravity 122 

Spot  test 125 

Standard  Engler  flask 17 

Stearine  pitches 158 

Sulphonation  test 151 

Sulphurized  oils • 187 

T 

Thermometer  readings,  correction  for 125 

Tung  oil,  acid  value  of 82 

anomalous  dispersion  of 80 


202  INDEX 

PAGE 

Tung  oil,  constitution  of 80 

domestic 84 

effect  of  climatic  influence  on 83 

heating  test  for 87 

iodine  jelly  test 88 

iodine  number  of 86 

normal  purity  of 82 

refractive  index  of 86 

regulations  of  New  York  Exchange 89 

specifications  for 84 

specific  gravity  of 84 

unsaponifiable  matter  in 85 

valuation  of 79 

variation  in  composition  of 82 

Turpentine 112 

density  of 30 

distillation  of 29 

polymerization 31 

refractive  index  of 29 

specifications  for 28 

U 

U.  S.  Bureau  of  Mines  Flash  Tester 26 

V 

Varnish,  determination,  of  metallic  driers  in 181 

of  volatile  thinners  in 180 

esterification  of 183 

identification  of  gum  constituents 191 

kauri  test 192 

separation  of,  gum  constituents 190 

oil  acids 189 

oil  and  resin 181 

unsaponifiable  in 182 

Volatile  thinners,  definition  of 115 

estimation  of 116 

aromatic  hydrocarbons 117 

increase  in  use  of 115 

loss  in  varnishes 121 

loss  in  grinding 119 

Volume  equivalents 196 

W 

Walker  and  Wertz  method 62 

Water,  combined 106 


INDEX  203 


Water,  in  containers 106 

determination  of 107 

estimation  of 105 

occurrence  in  paints 105 

Wijs  solution 171 

Wood  alcohol 35 

impurities  in 35 

Wolff's  esterification  method 183 

Z 

Zinc  oxide 138 

Zinc  soaps 134 

Zinc  sulphate 138 


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TP 

935 

E72a 

Engineer,.* 


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